After much request for better LT1 cam data, we have given in. It seems that many people are having problems with their searches and come away after reading numerous posts confused. There are countless posts and discussions already out there on this subject but we will attempt to make it more clear in this thread. I bet it would be safe to say that most people who mod their 305 TBI’s are first time modders. Meaning, everything that they do to their car is the first time that they have attempted that type of mod. They get past the basic bolt-ons like headers and such but now want to dive into more serious mods like a cam swap and chip tuning. I will not cover chip tuning at this time. Please read the links in the “new to TBI” sticky and “taking your TBI to the next level". Chip burning goes hand in hand with any cam swap for these cars. Also, please continue your searches for info on this matter. Revise your searching strategy or just keep trying with new words. I assure you that this stuff has been covered a million times and it is out there.

Okay, lets get started.

Here are a few links that can be found in the “new to TBI” sticky. They cover some of the basic information concerning an LT1 cam swap. Below are various threads that I dug up with a few minutes of searching.

Cam info 1
Cam info 2
Wide Band O2 sensor for tuning

Why the LT1 cam

As stated above, most people who mod TBI cars are first time modders. Chances are they have budget limits and want cheap performance accordingly. If they had more money, they would not waste their time with a 305 TBI. So, when it comes to heads and cam swaps they do not stray from that mentality. There is nothing wrong with going with a Crane or Comp cams camshaft. Those companies have amazing cams with second to none testing and customer service. They can recommend a cam that will be best suited to whatever combo can you can conjure up. With that comes price. It is not uncommon to pay up to $300 for one of their hydraulic roller cams. Not too many people want to spend $300 for a cam that is going into a 305. Sure it can be used in a 350 down the road but that is not the point. Plus, many of these cams exceed the limits of the stock heads. The stock valve guides can only really take up to .480” lift when in fact some may be as low as .450”. You can see where it would be pointless to get a really healthy cam and then keep any stock head castings untouched. Modifying the stock heads to accept a larger cam is also an option. With port work it has been proven that swirl port heads can offer decent flow numbers for low RPM motors. So now you understand the reasoning but don’t have money for a new cam or new heads or machine work to 416 or 081 heads. So you want a cam that is cheap, easy to tune (not to radical with overlap and duration), readily available, and compatible with the stock or other unmodified stock GM cast heads. Therein lies the LT1 cam. Its lift figures are just under what the stock heads can accept, is readily available, and can be had for as cheap as $30. They can be found in junk yards, car classifieds sections like www.camaroz28.com, www.ls1.com, www.ls1tech.com, TGO classifieds, and on Ebay. Here is a saved Ebay search for an LT1 cam.
If you have better heads such as the World products S/R Torquer 305’s or modified GM castings such as the 416, 081 or vortec heads I would go with a much bigger cam. It would not be the best idea to have a nice set of heads and the ability to tune your own chip and only have the LT1 cam to feed it all. An LT1 cam would still suffice and make power and pull strong to 5500 RPM, for this case a little bigger would be better. Ultimately you want to match your cam with the proper valve springs, intake and heads.

Identification

LT1 cams came in the following vehicles

’92 – ’95 vette
’93 – ’97 F-bodies
’96 vette (LT4 cam)
’94 - '96 B/D cars: Chev Caprice (sedan, wagon) & Impala SS, Buick Roadmaster (sedan, wagon) and Cad Fleetwood

The LO5 was not offered in passenger cars in 94-96; the last model year was 1993.
The LO5 was still available in C/K light GM trucks up to and incl the 1995 model year.

The bably LT1, aka the L99, was 265 cid which is 4.3 liters. It used the SAME cam as in the B/D LT1.

B-body cam information provided by kdrolt

Although both cams are hydraulic rollers, there are a few differences between the LT1 cam vs. your stocker. The LT1 cam has a much longer dowel pin at the end of the cam. This pin drives the opti spark ignition system found on all Gen II motors. The 93 and 94 LT1 cams had a much shorter dowel pin (non vented opti spark) and were close in length to that of your stock cam. Nonetheless you will need to either cut down the dowel pin or hammer it in. The stock one measures around 5/16” from the front face of the cam. As long as the dowel pin extends through the hole in the timing chain cam gear and does not come in contact with the timing chain cover, any length will suffice. Another difference between the two cams is the lack of a fuel pump lobe on the LT1 cam. This means that if you ever have a set-up that you wish to use this cam you will not be able to run a mechanical fuel pump. This pic here shows the two differences found on the LT1 and LT4 type cams.


LT1/LT4 cam


Stock LO3 cam (or any other Gen I roller cam like the L98 or LB9 will look like this)

Here is a link that outlines the different specs for various stock and aftermarket LT1/LT4 cams.

LT1 cam identification chart

You can also measure your cam to verify what cam you do have. Some people are unsure what vehicle their cam actually came from and want to know what they have. A caliper can tell you the basic specs of your cam. Use this chart to help you figure out cam specs.



The following Gen II cam info was provided by kdrolt

There were at least 4 Gen II v8 LT1 cams used by GM during 1992-1997. The F and Y cars each got their own, but the specs on lift and duration are very close for each --- as they should be because the cars weighed about the same (3200-3500 lbs typically). The B/D cars (Chevy Caprice, Buick Roadmaster, Impala SS for B-cars, Cad Fleetwood for D-car) used a cam with specs better suited for a 4200+ lb car. The durations and lifts were less than on the F/Y cars, because the emphasis was on better torque at lower rpms, with less emphasis on upper rpm power. This was a very acceptable compromise because the iron LT1 heads on the B/D cars were excellent pieces so the cam didn't need to be "big" to make excellent torque and power.

Two different B/D car cams were used in 1994-1996, but the specs for each are almost identical in terms of lift and duration. IIRC the lifts at the valve (via 1.5 stock rocker ratio) were 0.418" and 0.430" i/e in 1994-1995, and 0.414" and 0.428" i/e for 1996. There may also have been some crossover in 1995 where both the early and late B-car cams were used.

The B-car LT1 cam was also used in the "baby LT1" --- the 265 cid (4.3 liter) Gen II v8 known as the L99. Externally these engines look identical to the LT1, and the torque and power to displacement ratios for the L99 were almost the same as on the LT1. The main difference was that the power on the L99 peaked at a slightly higher rpm (5200 rpm) than for the LT1 (5000 rpm).

The B-car LT1/L99 cam was then used in 1996-1999 on the L31 5.7 liter (350 cid) Vortec engines --- which made some sense since the L31 was a Gen 1-type engine whose head patterns were literally copied from the iron LT1, and because the L31 engines were targeted at heavy truck that needed excellent torque and power (255 fwhp, 330 fw ftlbs). I don't know if the L30 (5.0 liter, 305 cid) version of the Vortec used the same cam, but it makes sense that it did given the engine rating of 230 fwhp and 285 fw ftlbs.

Parts you will need

Cam swaps should include new valve springs and a timing chain set. The stock valve springs are not designed to run with cams over or near .450” lift. High mileage also plays it toll on stock springs. They wear and fatigue over time and if exercised in a greater range of motion with a new cam they will likely fail or cause drive train instability. Here is a link that covers the basics behind valve springs. It is by far the most informative thread on TGO on this subject. There are many valve springs on the market that would suffice for an LT1 cam swap. I would however stay away from K-motion and the famed “z-28” springs. They are cheap for a reason. Stick with a comp or crane cams set and you will be fine. A properly matched set should run you around $50.

Valve Spring math and understanding If anything READ THIS!

In addtion to new valve springs should be a new timing chain set. Like the stock springs the timing chain will strech over time. The more miles the more likely is has stretched. You will want a new timing chain set to ensure the proper timing is kept throughout the powerband.

A popular spring choice for the LT1 cam and one similar to them are Comp Cams 249-981-16springs that retail for $60.
New timing chain sets can be purchased through GM Parts Direct under the part number 14087014 for roughly $30 (shipping and handling will tack on another $20). The same chain set can be purchased from Scoggin Dickey under the part number 12371043 for $50. Some people have retained the cam and crank sprockets of the timing set and just replaced the chain itself. The chain itself can be purchased at AutoZone or through Scoggin Dickey under the part number 14088783. Buying the chain only will save you around $20 or so.

Installing a new cam without changing either of these things may result in poor performance, broken parts and or damage to components.

New gaskets also need to be included with these mechanical parts. These gaskets will need to be purchased at any auto parts store.

Intake manifold gaskets (includes distributor and thermostat gaskets as well)
Timing cover gasket (includes water pump gasket as well)
RTV ( I like to use the grey or black RTV so that it blends in with the factory color of the motor)

Cliff notes parts list

Parts needed:
LT1 camshaft….Free-$50
Timing chain set – Part number 12371043 (from Scoggin Dickey)….$50
Valve springs – Part number 249-981-16 (from Jegs)….$60
Intake manifold gasket set – Fel-Pro MS93317….$15
Timing cover gasket set – Fel-Pro TCS45121….$8
Water outlet (thermostat) gasket- Fel-Pro 35062….$2
TBI unit gasket – Fel-Pro 60903….$7
RTV silicone sealant (gasket maker) and thread locker….$10
Fluids – Oil, coolant….$20

Optional:
Valve cover gaskets – Fel-Pro VS50088R….$15
Oil pan gasket – Fel-Pro OS34500R….$29
EGR valve gasket – Fel-Pro 7097….$2
Valve stem seals (intake) – Fel-Pro SS72527….$12
Valve stem seals (exhaust) – Fel-Pro SS72877….$18
note: Many people run intake valve seals on the exhaust side as well. They tend to seal better.

Prices are rounded off and do not include shipping charges. Prices will vary. These parts are only examples of what you can use for your cam swap.

Prices and parts were found here:
www.jegs.com
www.sdpc2000.com
www.partsamerica.com

Cliff notes parts lists provided by board member Benm109

 

Random LT1 cam threads

https://www.thirdgen.org/techbb2/sho...t=LT1+cam+swap

https://www.thirdgen.org/techbb2/sho...t=LT1+cam+swap

https://www.thirdgen.org/techbb2/sho...t=LT1+cam+swap

https://www.thirdgen.org/techbb2/sho...t=LT1+cam+swap

https://www.thirdgen.org/techbb2/sho...t=LT1+cam+swap

Valve spring threads

https://www.thirdgen.org/techbb2/sho...springs+to+use

https://www.thirdgen.org/techbb2/sho...springs+to+use

https://www.thirdgen.org/techbb2/sho...springs+to+use

https://www.thirdgen.org/techbb2/sho...springs+to+use

 

Installation

The majority of this swap took place with the motor out of the car. The motor DOES NOT have to be removed to perform a cam swap. I had my motor pulled for alternative reasons. The steps I have listed as based on the assumption that the motor is in the car.

Some of these steps can be done before others so I have certain ones in no particular order.

Step One – draining the coolant and removing radiator

The best way to drain the coolant from the motor is to locate the block drain plug on the lower driver side of the block. Unscrewing this will drain the coolant from the block, heads and intake. It is not necessary to start here but it will help keep you dry as well as preventing more of a mess than you will already create.
Locate the petcock on the lower passenger side of the radiator (see picture 1). It is plastic and has a flat face to it that allows you to unscrew it by hand or with the aid of a pair of pliers. Start to turn the petcock until coolant seeps out. A few more turns will allow the coolant to flow out. Make sure you have a lot of kitty litter and or mops/rags/towels handy to catch all the stray coolant. It is almost impossible to catch it into a container and coolant will run down every part of your front suspension. I like to put a large sheet of cardboard under the car so that when I have drained the coolant I can throw it away and have a fresh surface to lie on. Try to save as much coolant as you can because it can be reused provided it is not old or contaminated.
You can now begin to remove the radiator. Remove the two 3/8 bolts that hold the thermostat housing in place (see picture 2). Remove them and pry the housing free of the intake exposing the thermostat. Locate and remove the lower water pump hose. It is held on with a screw clamp. After the clamp has been unscrewed you can slide the hose free (see picture 3). Have a catch can ready to collect the remaining coolant that is present in the lower hose. Locate the four 10mm bolts on the top of the radiator shroud. Remove those as well as the two bolts that run along the bottom of the radiator (see pictures 4 & 5). There are six 10mm bolts all together. While you are down there you will need to unplug the electric fan. The fan assembly should now be free. It is attached to the shroud so as you pull up on it the fan will come with. You will now have to dissconnect the two collant lines that run from the overflow tank to the top of the radiator on the passenger side (see picture 6). After these steps have been taken you can lift up on the radiator and remove it from the car (see picture 7). Take precaution not to lose the rubber feet that seat the radiator.


Picture 1 - Petcock location


Picture 2 - thermostat bolts


Picture 3 - lower radiator hose clamp


Picture 4 - Upper shroud bolt location


Picture 5 - Lower radiator screw location


Picture 6 - overflow box lines


Picture 7 - radiator removed

Step Two – removing the water pump and crank pulley

Before you take off the serpentine belt it is a good idea to break loose the crank pulley bolts. The tension on the pulley created by the serpentine belt will prevent it from rotating as you loosen the bolts. There are four bolts that hold on the pulley. They are three 9/16 bolts and one 5/8 bolt in the middle. Loosen these but do not remove them yet. After they are loosened you can remove the serpentine belt and then remove the pulley bolts (see picture 8). Use a 1/2 drive and place it into the tensioner pulling counterclockwise on it. As you rotate the tensioner away from the belt you can slip it off. The crank pulley will now be off and the harmonic balancer will become exposed. You can now remove the water pump as well. Four long 9/16 bolts secure it to the block. After the bolts are removed it may become necessary to break the pump loose. The gasket adheres the pump to the block overtime see (picture 9). Be prepared once again to catch more coolant. There is no need to remove the water pump pulley at any time.


Picture 8 - tensioner location for serpentine belt removal


Picture 9 - water pump removed

 

Step Three – removing the distributor

The next step is to remove the distributor and plug wires. I like to leave all of the wires attached to the cap and remove the cap and wires as a whole. The cap can be removed by unscrewing the two hold down screws on each side (see picture 10). Because you will be rotating the crank later on it is not important to mark the distributors’ location in relation to some part of your motor. However, it will be helpful to mark the #1 plug wire to help line it up with the rotor later upon installation.
After you have the plug wires disconnected from the spark plugs and have the cap removed you can remove the distributor. It is held down with a tab that is bolted to the intake manifold. A 9/16 socket and or any special distributor wrench can be used to remove this bolt. The hold down tab will become lose and will need to be kept in a spot where it will not get lost. The distributor can now be pulled from the motor. Lift the distributor straight up by holding the underside of it. It will rotate slightly in your hand as the distributor gear disengages with the cam gear.


Picture 10 - distributor cap with wires

Step Four – removing the intake manifold

If you have not already removed the TBI unit from the intake manifold, now would be a great time. It doesn’t have to be removed but getting it out of the way makes thing easier down the road. Remove the fuel feed and return lines from the unit using a 5/8 wrench. It is recommended that you use a ¾ wrench as well so that you do not twist or bend the fuel lines. before you do this step it is wise to relieve the fuel pressure. To do so just unscrew the fuel cap and let the car sit for a few minutes. Most of the fuel will vacate the fuel lines. As you remove them you may want to shove a rag under the lines to soak up any residual fuel that may seep out as you remove the lines. You could also remove the fuel pump fuse and run the car until it burns up the fuel in the feed lines. From there, unhook all vacuum, throttle, and electrical connections from the unit and remove the three ½ long bolts that mount it to the intake manifold. The unit is now free and can be set aside (see picture 11).
To remove the intake manifold you will need to remove a few items from it. First you will need to unplug the CTS sensor located at the front of the manifold next to the thermostat housing. You will then need to disconnect the brake booster and rear coolant passage line from the intake. The brake booster can be removed just like you removed the fuel lines from the TBI unit (see picture 12). The coolant passage line can be removed by squeezing the clamp together and sliding it off (see picture 13). There is a brace that mounts from the intake to the AC compressor. This will need to be loosened and swiveled out of the way and off of the intake. The next items to remove are the coil and the throttle linkage bracket (see pictures 14 & 15). The coil has to be removed because it shares a bolt with the throttle linkage bracket. Remove the throttle linkage bracket and bent/place it aside. There are a few harness tabs that bolt to the top of various intake bolts. These will need to be removed before you can remove the intake bolts themselves. I no longer implement these tabs so I cannot remember exactly where they are on a stock car.
The intake is held down with twelve 3/8 bolts (see picutre 16). After these bolts are removed you can use a pry bar to break the intake loose. Sometimes you will need to use a screwdriver and smack it with a hammer to break the intake gasket and RTV seal. Try to remove the intake by lifting it straight up. There is still coolant in the intake and you want to avoid spilling it into the lifter valley of the motor.


Picture 11 - TBI hook ups


Picture 12 - brake booster line


Picutre 13 - rear coolant passage line


Pciture 14 - coil removal


Picture 15 - throttle bracket removal


Picture 16 - intake manifold bolt locations

 

Step Five – valvetrain removal

Now that the intake has been removed you can move onto the valvetrain. Start by removing the eight (four per side) 10mm long bolts that hold the valve covers on. Some covers tend to stick and you will need to tap them on the side with a rubber mallet to break them loose. The rubber orange gaskets can be reused so take precaution not to damage them. The entire valvetrain is now exposed. At this time it is a good idea to create or buy a valvetrian organizer tray/box. You will want to return the valvetrian parts to the same cylinder that they came from. Over time wear patterns develop into parts and you want to return them to their previous position.
You want to start removing the rocker arms. You will need a deep 5/8 socket for this. Remove all sixteen rocker nuts and set them aside in your organized container. The rocker arms will now be free and can be removed. All of the valves will now be shut. You can now slide out all sixteen pushrods. From here you can now remove the lifters and lifter plates. To do so you must first remove the lifter/spider hold down bracket that is bolted to the lifter valley of the block with three ½ bolts (see picture 17). Remove it and set it aside. You can now slip off the lifter hold down plates and slide out each lifter and pushrod (see pciture 18). If you are going to re-install these soon it is wise to soak them in oil at all times. If not, make sure to do hours prior to installation. At this point there is nothing touching the lobes of the cam. Now is also a good time to check the casting numbers on your heads. Make sure that they are consistant seeing how some people have had previous owners replace only one head. Most LO3's had the 187 heads with only a few having 416 or 081. The casting number is located on the top of the head around the rocker studs (see picture 19).


Picture 17 - lifter spider/retainer hold down bracket


Picture 18 - removed valvetrian


Pcitre 19 - casting number (187's on my '90 LO3)

Step six – removing the balancer, timing chain cover and timing chain

Before you can expose the cam and timing chain you must remove the harmonic balancer and timing chain cover. To remove the harmonic balancer you will need to rent or buy a harmonic balancer puller kit. This kit consists of three bolts that mount a cast housing to the front of the crank. A drive rod is screwed through the middle of this housing pushing on the end of the crank and thus sliding off the balancer (see picture 20). You can rent this tool from AutoZone for free. Make sure you thread the drive rod through the housing and place the triangular tip on the end before you start to remove the balancer. Without that tip you will mall and damage the crank snout. Removing the balancer takes a lot of muscle if it hasn’t ever been removed. If you find that you are turning over the motor without budging the balancer you have a few options. If your car has a manual transmission you can place the car in gear with the emergency brake on or you can remove the starter and slide a screw driver through a hole in the flywheel. The later choice is your best option to keep the engine from rotating.
After the harmonic balancer has been removed you can remove the ten 10mm bolts that hold the timing chain cover in place (see picture 21). You should be able to pull up and out to remove the cover but some find it necessary to drop the oil pan slightly. If you have to drop the pan, loosen all the bolts and drop the pan just a half inch or less. Make sure you do not damage the oil pan gasket as it can be re-used. (see picture 22)
After the cover has been removed the timing chain will be exposed. There are three bolts that hold the cam sprocket part of the chain assembly in place. Remove the three ½ bolts and slide the chain and cam sprocket off the front of the motor (see picture 23). The sprocket that is on the crank will stay in place. You will need a gear puller (also can be rented for free) to slide it off the crank. If you are just replacing the chain and not the sprockets (some choose to go this way if their motor has extremely low miles; high mileage vehicles should replace the whole timing set) you can leave the crank sprocket in
place.
From here you are almost to the point where you can pull the cam. First you must remove the cam retaining plate that is held in with two T-30 torx bits (see picture 24). This is the oddball tool of the whole swap. You will need to go buy a T-30 torx socket if you do not have one. I didn’t have a socket but instead have a T-30 torx screw driver. By using a pair of pliers I could get enough torque on the bolts to break them free.
After the retaining plate has been removed you can slide out the cam. I find it helpful to screw in the three cam sprocket bolts part way so that I can control the cam as I back it out (see picture 25). Back out the cam slowly and try to avoid banging it on the cam bearings. If the cam stops or hangs up you will need to rotate it slightly to reposition the lobes and it will come out (see picture 26).


Picture 20 - harmonic balancer puller


Picture 21 - removing timing chain cover


Picture 22 - timing chain cover removed


Picture 23 - cam sprocket removal


Picture 24 - cam retainer plate removal


Picture 25 - cam sprocket bolts in cam


Picture 26 - sliding old cam out

 

Step Seven – putting new cam in

Now that you have the old cam out the new one can go in. Hydraulic roller cams do not need to be coated in cam lube before you install them. They should however have a healthy coat of oil on them prior to installation. I like to use oil on the lobes and cam lube on the bearing journals. The new cam goes in the same way the old cam came out. I like to use those same cam sprocket bolts to aid with installation. Slide the new cam in slowly making sure you do not bash it into the cam bearings which you cannot see. The cam will drop each time to pass through a cam bearing so have a steady hand and try to avoid bashing it around. You will most likely have to play with the cam and rotate it to get it all the way in. You need to make sure it sits flush with the block so that the retainer plate will mate to the block face. At this point you can re-attach the cam retainer plate with the two T-30 torx bolts.

Note: If you have an '95 or later Gen II cam you will need to shorten the dowel pin. If it is not shortened it will rub a hole into the timing chain cover. The dowel pin can be hammered down or cut down to reduce its length. Match the length of the dowel pin that that of your stock cam.

Step Eight – installing the timing chain and getting the motor to TDC.

Now that the cam is in you are ready to re-install the timing chain and align the cam in the proper location. If you have a new timing chain set this is the time to install it. Remember, if you are replacing the whole set you will need a gear puller/installer tool to remove and replace the crank sprocket. If you are just replacing the chain you can leave the sprocket in place. For this particular swap I am not replacing the crank sprocket but I suggest that you do.
At this point you will need to rotate the crank so that the crank sprocket dot it in the 12 o’clock position. A crank turning tool as shown in pictures 27 and 28 is perfect and precise for this step. You use it with your ½ drive ratchet and turn accordingly. You can use a strap wrench or any other tool that may work. Be careful not to damage the crank snout and key or your balancer will not go back on.
Now that the crank sprocket is at 12 o’clock you can rotate the cam and re-attach the cam sprocket. You will notice that the cam sprocket has a little hole to accommodate the dowel pin on the cam. You need to install the cam sprocket so that the dot is in the 6’oclock position. To do so you will have to rotate the cam so that it fits into the cam sprocket. It is a tad tricky since you have a tendency to overshoot any cam adjustment. You can turn the cam by simply pushing down or up on the dowel pin. It will rotate slightly to where you need it to be. If you get the cam sprocket in place with the dowel pin through but don’t have the bolt holes lined up, don’t worry. You can hold the sprocket still and just take stick a thin screwdriver through the bolt holes and turn the cam slightly. Re-install the cam sprocket bolts (three 1/2 bolts) and double check that your crank sprocket dot is at 12 o’clock and that your cam sprocket dot is at 6 o’clock. You are now what is commonly referred to the “dot to dot” position (see picture 29). The two dots should be right on top of each other and your motor is now at TDC for #1 exhaust and #6 firing. If you are sure you are aligned correctly you can rotate the motor using your crank tool one full turn so that the crank sprocket returns to 12 o’clock but the cam sprocket will also be at 12 o’clock. The motor will now be at TDC for #1 firing and #6 exhaust. The reason you start with the “dot to dot” position is that it is easier to align the dots this way to ensure correct cam placement.


Pciture 27 - crank turning tool


Picture 28 - crank rotating tool


Pciture 29 - dot to dot alignment of the cam and crank sprockets

 

Step Nine – valve spring replacement

Now that the cam is in you can install the new valve springs that match with your cam. There are two methods for changing valve springs and one is better suited than the other.
The first method uses compressed air. For this method you need buy an air adapter the screws into the spark plug boss. These can be purchased from any auto parts store. You fill the cylinder with air so that when you remove the valve locks and springs the air pushes the valve up against the seat and keeps it from dropping into the head (see picture 30). This method is almost impossible to do with the engine in the car because headers get in the way or air lines. In addition to this the exhaust valves don’t always stay up with compressed air. I have tried this method a few times and absolutely hate it.


Picture 30 – compressed air method

The next method involves nylon cord. Get a hold of some nylon cord and feed it into the spark plug boss. Shove as much as you can into the cylinder filling it up. The nylon cord will support the valves and keep them from falling into the heads.
There are many valve spring compressors on the market that range from cheap to expensive. I have had luck with the ultra cheap ($10 IIRC) Morroso compressor. You simple slide the compressor over the rocker stud and use a rocker nut to secure it in place. Pull on the compressor which will compress the spring and expose the valve locks. Use a tiny magnet to grasp the locks and pull them free from the valve tip. You will have to do this with one hand if you use a cheap compressor. Once the locks are out you can unscrew the rocker nut, remove the compressor and slide the valve spring off. Installation is reverse of removal. At this point it behooves you to change the valve seals. You have the motor in the perfect state of disassembly to perform this swap. Seals are cheap and will prevent that annoying puff of oil smoke many of us see on start up. Refer to the archives of TGO to determine what seals are best for you as well as installation hints.

 

Step Eleven – Harmonic balancer installation

Now that you have the timing chain cover and water pump put in place (the water pump can be installed latter if you wish) you can proceed to putting the harmonic balancer back on. To install the balancer you will need a tool similar to the one that you removed it with. Like the removal tool the installer tool can be rented from AutoZone with a small deposit. Before you install the balancer you need to make sure that the mating surfaces of the crank snout and balancer are clean and free of any dirt. Wipe both surfaces off and apply a thin layer of grease. Place the balancer on the snout so that the key (raised portion of the crank snout) is aligned with the slot in the balancer. The harmonic balancer tool screws into the front of the crank with a bearing filled spacer/bushing on the outside surface of the balancer. Make sure that the installer tool is threaded as far as it can go into the crank. You can now tighten the nut that pushes the washers against the balancer. This will push the balancer onto the crank. Go slow and pay attention to the movement of the balancer. It is easy to strip the crank snout threads if you are overly aggressive. When the balancer is fully seated you can re-install the crank pulley. (now is a good time to put some white paint in the balancer groove; this will make the timing marks show up far better when you hit it with the timing gun).

Step Twelve – Intake manifold installation

Before you can start re-installing the intake manifold back on the motor you need to make sure you have done the proper surface preparation that is needed. You must ensure that all old gasket material has been removed from the intake manifold and from the surface of the heads. A gasket scraper that implements a razor blade is invaluable for this step. I like to buy a can of gasket softener/remover from any auto parts store and spray it liberally onto any old gasket material. After it soaks in, the dried up gasket chunks become a little more pliable and can be scraped off a little easier. I find this part of the cam swap to be the worse. You need to spend a lot of time ensuring that your gasket mating surfaces are as clean as can be. If they are not the new gasket will likely not seal and you will have an internal vacuum leak. (air being sucked into the crankcase via lower intake gaskets). You don’t want to have to pull the intake again so make sure you are down to bare metal. After you reach this state you need to wipe down the gasket mating surfaces with mineral spirits and or brake cleaner to remove any oil film that may be present. You are now ready to install the intake.
At this point you can now lay out your new intake manifold gaskets on the surface of the heads. These gaskets will have the tendency to slide down into the lifter valley when you let go. To prevent this I like to take an old pencil and break in into four 2” sections. I slide each section down through the bolt holes in the gaskets into the heads. These pieces will act as studs and will keep the gaskets in place as you lower the intake onto them. There is nothing more annoying than trying to seat your intake with slipping gaskets. The pencil trick will prevent this and keep the gaskets still.

Note: Some people like to put a thin film of RTV sealant around the coolant passages of their intake gaskets. I have always put my gaskets on dry and have not had any subsequent leaks as a result of not doing so. However, if you are leery you should apply a thin layer of RTV for nothing more than piece of mind.

You can now start to prep the front and rear china walls of the block. Wipe down the top surface of both the front and rear china walls with brake cleaner and or mineral spirits. You need to strip the surface of all oil so that he RTV will adhere properly. With the intake gaskets in place proceed to apply a 3/8” thick bead of RTV to the china walls. Make sure to overlap your RTV bead onto the two tabs per intake gasket that seat on the block. I like to overlap my RTV bead at least ½” onto the intake gasket tabs. The pencil pieces will keep the gaskets from moving as you apply the RTV. You can now lower the intake manifold into the top of the motor. Make sure to feed the pencil tabs through the intake bolt holes to endure proper gasket alignment. After the intake has been seated immediately feed a few bolts to secure it. Before you feed any bolts it is a good idea to coat them with a small dab of RTV or thread sealant. This will prevent oil and coolant from seeping up the threads and pooling on your intake surface. I prefer and have always used a small squirt of thread sealant to prevent this potential ugly side effect. Do not tighten the bolts but get a few started to seat the intake. Once you have a few started a few bolts you can pull out the pencil tabs and put in the remaining four bolts. Tighten the intake between 20 and 30 lb ft using a torque wrench. If you do not have a torque wrench you will have to use the old hot rod wrenching slogan, “tight but not too tight.” You want to tighten the intake from the center bolts and work your way out to the outside bolts. Make a few passes with your wrench on each bolt before you tighten them down all the way. If you tighten each bolt all the way from the get go you risk warping your intake. Let the RTV sit for at least six hours prior to starting the motor. The RTV needs time to set up and solidify.

*pictures to come for these steps*

 

Step Thirteen – Valvetrain re-assembly

At this point you can re-install the lifters, pushrods and rocker arms. Before you install the pushrods and lifters it is important that you soak them in oil for a few hours prior to installation. After soaking the lifters in oil slide them down into their appropriate holes in the block. Slide the lifter retaining plate over them. You may have 6to rotate the lifters to get the plate to seat correctly. They have two flat sides to them that keep the lifter from rotating once installed. Once the lifters and plates are in place you can re-attach the lifter retainer/spider bracket. It is held in with three ½ bolts and may require you to push down on it to seat it against the block. The tabs are preloaded in a sense to keep the lifter plates seated. You can now slide the pushrods back in place making sure that they are seated and centered into the top of the lifter. You only need to slide them in at this point. Next you will need to place the rocker arms and bolt them down. Don’t tighten them down too much. At this point you need to set the valve lash. There are many ways of setting the valve lash. You can do it with the engine cold or with the engine hot. I have done both methods and I almost prefer the hot method.

Method one: Cold adjustment

Place the engine at #1 TDC. You should already be here if you followed the timing chain install correctly. If you are unsure you can place your finger over the #1 spark plug hole and rotate the motor. When you feel the pressure build up against your finger you are close to TDC. Stop when the balancer grove aligns with the 0 mark on the timing tab. To adjust a valve, slowly tighten the rocker arm nut until all clearance between the pushrod and rocker arm is removed. This is zero lash. Tighten the nut another ¾ turns to preload the lifter. To ensure that you are at zero lash observe the following tips

-Move the pushrod up and down until all the clearance between the pushrod and rocker arm is removed.
-Spin the pushrod as you tighten the rocker nut. As soon as you feel some drag on the pushrod turn the nut another ¾ turn and stop.

Now that you know how to properly adjust the valves you need to do so in the following order.
With the #1 piston at TDC adjust the #1, #2, #5 and #7 intake valves and the #1, #3, #4 and #8 exhaust valves. Rotate the crank (using your crank tool if you haven’t installed the balancer yet, or by turning the crank bolt after the balancer is installed) 360°. The motor will now be at #6 TDC firing and #1 TDC exhaust. Adjust the #3, #4, #6 and #8 intake valves and the #2, #5, #6 and #7 exhaust valves as mentioned above.

Method two – Hot adjustment

After you have the motor fired you can adjust the valves. If you haven’t put the motor back together you will need to hold off and return to this step when you are ready. You will need to do the adjustment with the valve covers left off. This can be messy so be prepared for a little clean-up afterwards. You will adjust the valves one at a time. It doesn’t matter which one you start with but I like to start at the front of the motor and work my way back. Back off the rocker nut until you hear the rocker start to make a loud clanking/ticking sound. Tighten the nut slowly until the noise goes away. You are now at zero lash and can give ½ to ¾ more turn to preload the lifter. Adjust each valve after the same way.

Step Fourteen – Distributor installation

Now that you have the intake manifold installed you can put the distributor back in. To do so make sure that you have the distributor cap left off so that you can watch the movement of the rotor. Before you start make sure that the motor is at #1 TDC. It doesn’t matter if you are on the firing stroke or the exhaust stroke. You will determine that by your placement of the distributor. You can now slide the distributor back in. As you install it make sure that you do so with the rotor pointing towards the #1 cylinder and plug wire route. This will make things easier down the road and will keep the distributor in the stock location so that you can follow the plug wire route diagram found in any repair manual. As you slide in the distributor it will rotate slightly as the distributor gear meshes with the cam gear. When it is seated ensure that the rotor points to the #1 cylinder at the front of the motor. If it isn’t quiet pointed right you can pull the distributor, rotate it just a hair, and slide it back in. You can now screw the cap back on. This is another perfect time to ensure that you line up the rotor with the #1 cylinder. Use your markings that you previously put on your distributor cap to verify that the rotor is pointing to the #1 terminal. Place the hold down tab in place and tighten the 9/16 bolt down. You can now install the plugs and plugs wires in their proper routing. Refer to a Haynes and or Chilton’s manual for the correct diagram.

Step Fifteen – Setting the timing

Now that you have everything installed and put back together you can fire up the motor and set the timing. If you were careful enough to make sure that everything was aligned and positioned according to the #1 TDC position of the motor it should fire up without much effort. It may turn over a bit before it builds oil pressure as well as re-filling the fuel lines that were previously emptied. After the motor fires you can proceed to set the timing. Get your timing gun ready and clip the power wire to the positive terminal of the battery as well as the main wire to the #1 plug wire. The timing gun is now in sync with the motor. Locate and unplug the EST wire (see picture ??). The EST wire is located on the rear of the motor near the firewall on the passenger side. It is commonly found near the strut mount or just aft of it. Unplugging this wire disconnects the ECM from the distributor. The motor may stall if the timing is too far off. The reason it most likely won’t stall with the EST plug is that the ECM will make corrections to keep the motor running. Hold the timing light over the timing tab and read the mark that the light blinks on. If your timing is way off you will see the balancer slot light up off the timing tab. To advance the timing you want to loosen the 9/16 hold down bolt (do not remove it, just loosen it) and turn the distributor clockwise to retard the timing and counter clock wise to advance it. Try to turn it with one hand while you point and monitor the light on the balancer and timing tab. Sometimes it helps to have a buddy turn the distributor for you. Turn it until you reach your desired timing setting. Most LT1 cam swaps will need 8° or more advance to keep them running on the stock tune. If you set it to the factory 0° the motor will most likely stall. When you have set your timing you can re-plug the EST. It is now a good time to unplug the negative battery cable to re-set the SES light that is tripped by disconnecting the EST.


Picture ?? – EST wire connection

 

Please feel free to post your thoughts, questions and concerns at this time. I won't be able to get some additional photos for a few more weeks so I my progress is at a slight stand still right now. I want to make this swap as easy as possible for people to understand. If you see a correction that needs to be made or a step that needs to be further clarified please post up or send me a PM. Also, please ask questions if you are unsure of any step. There is no such thing as a stupid question when you are dealing with a mod of this magnitude. I want to encourage people to mod their LO3 in this mannor and I know some people may be lost. I will respect all comments and critisism.

Thanks guys.

*More pictures to be added as time goes on*

 

Awesome work Shifty-
S-D

 

Before you slap on the intake
Check all the push rods after Torqing down the rockers
and turn the engine over, i ended up with a 1 bent push rod
it was set in there right and TQ down to OEM specs but im asuming it just gave out and bent, the other 15 are fine, if it happens to you like it did me you can just go to an auto store and get one, if there out you can order one at the store and should be there ready to pick up in a few days, its no more then a few bucks, just thot id add this

 

Good points.

You must have over torqued them without setting them correctly. Pusrods don't have much pre load force on them if you set them correctly. You should just tightten them down to get them started then procede to adjust them accordingly.

 

Wow Shifty, thanks alot!

You are truly an extremely reliable source of help.

This swap will have me knowing more about the internals of my SBC and will also help me pick up a couple more HP in my L03.

VERY nice work man

 

I can this FAQ for my 305 tpi?

 

You sure can. The only real difference is just going to be removing and reinstalling the intake, just because the TPI motors have more stuff on top to remove, like the plenum, runners, etc.

 

Thanks! Btw, how much of an hp gain can be had with the LT1 cam?

 

With the right fueling, chip work and supporting mods you can see 25+hp.

 

Heres a picture of a 93 LT1 cam with the shorter dowel pin

 

While your at it you might as well take the heads off and lap the valves. Also remove the springs properly while the heads are off, cause it looks like that pry bar will cause damage to the threads, on the studs, as well as possible cracking of the head.

 

Also, is it necessary to replace the lifters?

I want everything running reliably because it's my daily driver, but I really don't feel like spending $200 on new ones if my stock ones will last through this cam.

So my question is, will the lifters hold up to the new cam? My engine has about 135k on it.

 

No, you only really replace lifters if they go bad (of course ). As long as the ones you have now are fine, don't worry about them. Most people do not replace lifters when installing a new cam, unless they have a flat tappet (hydraulic or not) cam and lifters. Our cars use roller lifters, and they do not wear like flat tappet lifters do.

 

Thanks for your response, and I completely understand.

Except... how do you actually know if the lifters are bad? Can you visually inspect them or do they make noise when going bad?

 

Check the tips to make sure that they still roll free and do not snag, bind or catch. Also. turn the motor over with the intake manifold off and watch the pushrods press into them. Make sure they all prime (the pushrod will push down a plunger in the center) up and down freely. Roller lifters last a very long time. You really only need to replace the valve seals and springs.

 

Shifty, if i install the cam on stock tune, will i still be able to see a gain? I have no way to tune or make my own chips, let alone know anybody who knows how too.

 

You may see a slight gain in your peak power but everything else will stink and your car will be slower. The motor won't idle well, it will surge, hesitate and eat gas. The car will be what I call an "undrivable mess". You are better off with the stock cam until you learn how to chip tune. If you are serious about a cam swap you need to be equally serious about the chip work. You can learn everything here on TGO (DIY PROM board as well as TBI board) and you can buy all the stuff for around $200.

 

Thanks man. You been a big help man, I'll do some studying before i jump into it. Thanks again.

 

WOW. Thats the info i needed. i got online thinking "theres no way I'll find EVERYTHING i need to know about a basic cam swap". I was wrong. Guys like me really appreciate guys like Shifty helpin us learn. Thanks Shifty.

 

Shifty, just got cam and timing chain in mail yesterday. Still gotta get all gaskets and then the green light is waved. I'll definitely post results (not dyno, don't know of one in the area) on how well the car responds to the cam. Should be done in 2 or 3 weeks. Just waiting for a really warm day. Just been so cold here in Boston.

 

Sounds good. Get ready for a long weekend of wrenching. Go slow and mark your bolts. Are you doing chip work at this time as well? Don't be shocked when your car runs less than what you hoped for upon inital start up.

 

Yes. Chip work is been done aswell. It's well known now that it would barely run well without chip work, so i'm gonna get that done too. And yes, it's gonna be along weekend indeed. Some soda and sandwiches, i should be fine .

 

Stupid question time:

I appreciate the great write-up but have a question.
In the re-assembly sequence you are installing the intake manifold before installing the lifters. That doesn't make sense to me. I don't see how to put the lifter retainer plate bolts on when the intake is already on? Am I missing something?

Thank you for the clarification

Scott

 

You caught a serious error in my ordering! Wow, no one has brought that to my attention.

The lifters must go in before the intake is put back on. The first part of step 13 needs to happen before you install the intake.

I will update and correct that error. Thanks for the heads up!

 

FYI, I prefer to set lash before I even install the intake. It makes it easier to feel the pushrod, and find zero lash.

 

Completly true.. I just installed an lt1 cam on the stock tune and guess what, its an undrivable mess

 

Modding the LO3 was doubtful for me, and then I read this cam swap guide. GREAT work Shifty. I still have exhuast, intake, and chip work to learn, but now cam work is a possibility. BTW, you could publish this in a book.

 

It still needs a little work so stay tuned. I am now just a few months away from getting my car back on the road.

 

ok I know this is an old thread but very useful...thanks alot shifty!!
Now I have a Question...I am putting a 350 out of a '93 silverado in my 92 rs..The guy at tbichips.com told me to get an lt1 cam(which I got for free...it come from a 95 camaro) and that would up my rpm range from the lower torque range of the truck cam...he also said for me to just use all of my roller stuff out of my engine.....is the truck engine tapped for the lifter retainer bracket?and can I use 1.6 rockers without a spring change?I'm forgetting something I know but I'll write back if I remember...Thanks

 

Not all truck motors were roller. However, most had provisions for a roller cam already machined into the block. They just used a flat tappet set-up in place. If that is the case you will need to tap a few bosses if your motor is not. Look in the lifter valley of the motor and see if you can see the three bosses that are present for the spider bracket (that holds the lifters down). If you see these chances are your block has the roller provisions cast in place. You will also need to tap the two holes for the cam retaining plate. You will not be able to use any of the truck valvetrain (unless it is roller) with an LT1 cam. At the least you will need to use your lifters from your current roller 305 set-up.

I would not run 1.6 rockers with an LT1 cam unless you have the heads machined for a higher lift cam (valve guide work) and have the pressed in studs removed for screw in units (cams around max lift for stock heads risk pulling out the stock studs).

 

Im a little confused.
I have now a 94 lt1 cam, for my 91 firebird lo3. How do I solve the "fuel pump lobe" issue? Does my car have a mechanical one?
Id really appreciate your help.

 

Your TBI set-up uses an in tank fuel pump and does not use a mechanical pump. You do not need to worry about the fuel pump lobe. Some people chose to use a carb instead of TBI and will use a mechanical pump instead of retaining the stock in-tank electric unit.

 

Regarding machining for high lift cam, it seems the Beehive springs would work, they'll allow .550 lift without machining. However one needs the retainers and locks as well.

 

Old thread but I have a question. Have you/ are you degreeing this cam and at what benefits?

 

how much power does an lt1 cam add to a 305 tbi engine?

also, since the cam fits, will the crank fit? both can be found on ebay for $30 each, so if they both work and make any power gains at all, why not?!

 

I think it's been said that an LT1 cam with tuning is between 25-35 hp increase. correct me if I'm wrong.

 

well thats a really good increase for a $30 part!!!

i wonder about the crank too, (if it fits) they can also be bought for $30 on ebay.

 

25-30 hp is not unhead of, but the key really is tuning. You may actually loose power if your tune is already stretched to it's limit with exhaust or other mods.

The crank will fit, but the stroke of a 305 is the same as a 350 so there will be no HP gains. The LT1 crank is cast just like most stock SB's so there really aren't any strenght gains to be had. You also have to keep in mind that the LT1 crank will be balanced differently than even a gen1 350 because the LT1's use light weight mahl pistons and lightweight PM rods that weight a good bit less than the older stuff GM used to use. h

 

Question regarding LT1 cam identification,

I mesured and substracted the base circle from the hight of the lobe multiplied for 1.5 to find the lift. I did it to the first and third lobe of each cam.

I got the following lifts for each cam:

#BC.11...242.GMPT, .460"/.449"

#BC.1...241.CPC, .459/.449 (this one has already the short dowel pin)

#BC.17...242.GMPT, .459/.449


According to the LT1 identification chart abowe, all tree should be GM 94-95 LT1, duration230/208, 1.5 lift.450/.460 and lobe116 cams.

Is this how u identify a cam? And any sugestion on wich one to use? Thanks.

 

Everyone talks about putting in a LT1 cam in a 305. I have a 350 firebird that had two spun rods. I had gotton a 350 out of a 93 truck and used the truck heads put in an new LT1 cam and New rollor lifters the set cost $400 though GM after rebuilding the 350 I used the firebirds pushrods and the TPI. And did no other mods to the car and it runs like a raped ape. So my question is there a difference in the 305 computer vs the 350 computer that I didnt have to do any other mods? And What are the benifits to putting and LT1 cam in a 350 engine?

 

The stock LT1 cam is not _that_ much different than some of the TPI cams, so I’m not surprised at all if it ran fine with an L98 ECM. WRT to the power that it makes, how it feels is really somewhat irrelevant without real numbers. There are 13s cars out there that feel like complete beasts, 11second cars that are totally tame, and 14 second cars can scare most of the public.