85TAracer

iTrader: (5)

Hey guys. I am about to build my first LT1. It is going in my 85 TA. I will be using the T-56 also. I have rebuilt a 68 327 and an 80's 350, both were carbed. This will also be my first injected engine.

The engine is tore down (had approx. 80k on the clock) and looks clean. I have bought very few parts on purpose, because I don't have enough LT1 specific knowledge yet. (This is where I defer to you guys) To throw another nut in the intake, I plan to install nitrous after the engine is broken in.

So, here are my goals and ideas, and I look to the experienced guys on here for some help in chosing the correct parts to install to achieve the horsepower and reliability I want:

Street car, will see track time, mostly 1/8 mile.

Would like to get around 400+ HP at the wheels from the engine.

Would like to use direct port nitrous, starting with a smaller 125-150 shot to learn tuning techniques, with the goal to eventually run a 200 to 250 shot, depending on the additional strength (engine or otherwise) required to hold up to 250 shot.

With these goals, I have a few questions:

1.) Can direct port be used with the stock intake? (ported)

2.) What aftermarket heads will work good with nitrous, give me the flow to produce the HP needed, and still be streetable? I am thinking about a set of AFRs, but don't know which.

3.) Cam choice. Nitrous specific or just spec'd to give me the HP

4.) rotating assembly - need help! crank rods pistons and rings!

Lets start with that for now. I know its a lot of info, but anything you guys can give and any time you can spend typing is extremely appreciated!!!

Thanks,

Tim

brandoz28

iTrader: (1)

1.) a direct port should be able to be used with the stock lt1 intake
2.) afr's are a good head, 195's would probably get it done, make sure you get ones for the lt1
3.) you're not spraying enough nitrous to make use of a nitrous specific cam worthwhile
4.) i would probably get eagle everything, and get everything forged, you may be able to get away with going cast crank, but i wouldn't risk it.


overall if you're only spraying a total of 200 ever, i wouldn't worry about using a plate

fireturd350

iTrader: (8)

Anymore now days choosing between a Forged 4340 and a cast crank assembly is a no brainer forged has gotten so cheap in price. Forged will be alot more forgiving also especially once you decide to push it past that 150 hp shot.

CompCams or similiar company can provide options or just flat out tell you what they recommend for camshafts based on your specs and purpose.

Unless you plan on turning a crap ton of RPMs theres not much need to go over the 195s in AFR. I went with the 210s but I'm running a solid roller setup.

Drac0nic

If you do a full rotating assembly I'd just get a 383 setup especially if you do AFR 195s. If all you're looking for is 400 at the wheels with a 250 shot you should be able to do that with a set of pistons and H-beams on a stock engine with a mild to moderate cam. With little trouble. The stock engine made about 300 with no mods add a good cam to it you'll be way above that add 250 of spray on it you should be nearer to 500 at the wheels with the supporting mods required. Shoot with a 383/AFR 195s you could likely do 400 at the wheels or damn near it without any spray at all.

I'd be willing to go far more conservative and try slugs/h-beams on a stock reconditioned or 1053 crank (like a ZZ3 forging) for 400 at the wheels. It would take it fairly handily throw some main studs in the bottom end port the stock heads, get a decent cam/matching valvetrain and call it a day. Just my vote.

ED:using a stock intake with port injection isn't a huge deal. If you wanted to get really nasty stick it under the intake. Will be a hell of a lot more fun even though changing jets on it will be a hell of a lot less fun :P

built91Z28

Dont forget about the other stuff though on the car when building a motor like this. Things like fuel system, good exhaust, and rear axle get overlooked sometimes when planning the budget for the motor. Also make sure the trans is going to like having over 600 horse going through it when on spray.

The way I read the OP's first post is that he wants 400 to the wheels without spray. Thats the way I took anyways.

Orr89RocZ

iTrader: (20)

200-250 shot may want a slightly different cam than normal aspiration to get abit more benefit from the spray. 150 shots you dont need anything special. I'd go with a 383 since you will want forged everything for that much of a hit, and it doesnt really matter what brand you go with for the internals. I've used Eagle in my nitrous 383 just fine, and I have callies in my turbo motor. Just get good rod bolts...arp 2000 should handle whatever you want thrown at it. I'm over 800-850hp on my motor with no problems yet to the rods and i dont expect any.

383 will make 400 at the wheels much easier than a 355 and the price is about the same so more torque is a bonus. AFR 195's are good but so are aftermarket ported LT1 heads. Advanced Induction is a good place to look. AFR 210s wouldnt be bad with a 250 shot either. It would make sick power.

I'd go around 11 to 1 compression and cam to match...should peak in the 6200-6300 rpm range so only need around 230-232 deg of duration if done right. 8-10 deg split should work well on the bigger hits but still give great 150 shots and n/a performance. Hell i ran 15 deg split on my car and it made 400whp with a nice broad torque curve and hp curve up top. Loved nitrous too but I only sprayed 150 shots.

Ring gap needs opened up a touch for the 250 hits. I think I had a .018 gap top ring/.020 second on my 383 which was good for 150 stuff. Higher shots probably want to try around .023 top/.025-ish second. I have to check my turbo motor specs but cylinder pressures should be fairly high with a 250 shot so it will need the wider gap. I think I have .022-.023 top ring and .025 or so second.

85TAracer

iTrader: (5)

great info so far guys! Yes I am shooting for 400 RWHP n/a, then spray on top. I just bought a set of Lloyd Elliot heads, and he is making me a custom billet cam for all the specs I gave him. I thought about the 383, but for this engine I think I'm going to stick with a 355.

Head specs: fully ported, 205cc intake ports, 5 angle valve job, Manley 2.00/1.56 valves 52cc chamber.

Potential cam specs: 232/240 592/592 with a 110LSA

Other issues: I have upgraded the fuel pump to a Walbro 255, I am running long tube headers that I had on my 327, and will be building a new dual exhuast to replace the one I currently have. (or I may consider building a dual 2.5 merged into a single 3" out the back) I will be running a Denny's driveshaft into a 9 bolt posi for now.

Orr89Rocz - With those heads what pistons should I run to achieve 10.5-11:1?

Orr89RocZ

iTrader: (20)

You'll want around 12-16cc dish. 16 gives 10.4 roughly with a .041 gasket and zero deck. 12 gives about 10.94... Thats the range you want and those are fairly popular piston dish sizes. Check the piston the valve clearance carefully with that cam I like the specs, and capable of making 400 whp with his heads and ported intake on a 355. Seen those setups many times on camaroz28.com

85TAracer

iTrader: (5)

So the block hasn't gone to the machine shop yet, and I forgot to mention the heads are cut .030. The block is stock. I am going to have the shop clean and check the block, bore it, replace all plugs and install the cam bearings. Do I need to have them do anything with the deck? Also, besides the thickness of the head gasket you recommended, is there anything else special about it that I need? EX. special for nitrous app?

Roller rockers: with this setup what should I run? 1.5 or 1.6? other than matched springs for the cam, do I need any fancy parts like guideplates and screw in studs? One more thing, along those same lines, what puchrods do I run?

I really appreciate the help guys. This is my first "high performance" engine. Once it is done I will have learned enough to tackle the next build with more confidence and ability to determine these things myself. I am using this as basically "school" lol.

Thanks again,

Tim

built91Z28

I thin most full roller rockers are non self aligning and require guide plates, which require screw in studs. I wouldnt build a 500 hp NA motor and spray on top of that without screw in studs. Plus with the size of that cam, get the screw in studs. As far as which ratio, I would contact Loyd Elliot and see which rockers he speced the cam with.

Edit: dont forget that guide plates require hardend pushrods. Dont just buy factory length either. Get an adjustable rod and measure to see what your motor wants.

Orr89RocZ

iTrader: (20)

I like to have my setups zero decked so i can use a thicker .041 gasket but some guys dont want to zero deck the block so they can get a rebuild out of it. Usually in that case, a shop will shave off just enough to ensure a smooth flat surface. Deck may be between 9.010 and 9.020 instead of zero deck height of 9.000. If its cleaned to 9.010, run a .030-.032 gasket. If 9.020, run around a .020-.025 gasket. I'd stick with an MLS type gasket from Cometic. I've run Felpro on my cars and they worked well too however I heard that the new felpro MLS gaskets have a different coating on them that doesnt seal as well as before. Some guys have reported problems with them. The new ones are blue colored and the old were black. I ran the black ones on my 383 and i think i have the blue ones on my 401 and I dont think I have any problems but i do have crankcase pressure problems under boost. Dont think its a head gasket leak at all since my car doesnt push water. Oh well....

that cam is probably for 1.6 rockers. I dont think you can get a .592 lift cam with 1.5's Screw in studs, preferably 7/16 inch studs for extra strength. Those heads should have good springs with good spring pressure for that cam. Lloyd has been doing those setups for a long time. That cam will likely turn to 6800 rpms so definately need valvetrain stability. that cam is almost as big as my 383 cam and it peaked at 6250 but held flat to 6500 and shifted by 6600-6800

Nitrous will likely peak alittle earlier than n/a however. Most setups seem to do that.

85TAracer

iTrader: (5)

Update: I have collected a few parts for my setup. The remaining parts will be purchased over the next month as extra cash comes in. I do want to nail down what those components will be. With the info you guys have provided I should be pretty much set.

So, the update is I received my new heads and cam. I have a 58mm Holley TB and ported intake on the way. Also an aeromotive adjustable fuel pressure regulator.

I ended up going with a smaller cam, one Lloyd had ordered for a customer and they backed out, so I got a great deal on it. The specs are: 230/236 .565/.568 110 LSA

The heads are all set to accept screw in rocker studs as well, which I didnt realize (an added bonus!)

Here's a question that may need to be posted at LS1Tech - what # fuel injectors should I buy? I'm thinking the nitrous will be using the injector for the added fuel, rather than stand alone, so they need to handle the extra flow...

I will update as I buy more parts, and if I have any more questions.

Thanks,

Tim

Orr89RocZ

iTrader: (20)

IF you run a wet kit with fuel source tapped into the fuel rail, then you wont need too much injector. 36's will cover everything. Even 30's has a good chance of supporting 400 whp but 36's give more safety.

A dry kit will need alot of injector for a big shot but I dont know of many people running a big 150+ dry shot.

Cam looks ok. I would have expected abit more lift and duration split with a potential 250 hit but for up to 200 it will work great.

85TAracer

iTrader: (5)

So can I run some type of splitter into my fuel line? I'm sure theres an easier way, but I think I would have to tap in after the plastic line meets the steel lines running to the back, and then just have a second pressure reg. for the one going to the nozzles. (I have an adj. reg. in the stock location for the base engine)

I don't think ill end up going up to a 250 shot, this car will be built solid, but its not a race car. I dont want to push the limits of the driveline more than I already will be, I dont want to be buying pricy tranmissions and rear ends...

Orr89RocZ

iTrader: (20)

I'd just tap off the schrader valve. If not, you can run 1 regulator. Have supply line go into 1 rail, do a crossover, then out the back rail into the one regulator. Before that regulator, you can Y off it possibly and run one line to the nitrous fuel solenoid.