91RockS

I'm getting everything lined up to make my 305 motor upgrade. Last thing to buy is the cam. I'm looking for good streetability with occational trips to the track, with 300 FWHP target. I'm by no means an expert DIY tuner, but I'm good enough (I think) to work my way through this next step. Here's what the cam will be matched with :

T5 manual trans
L03 stock lower end
081 ported heads 1.94/1.5 valves
Holley 300-66 Projection TBI intake
46mm high flow TBI with ulitimate mods
Bigger injectors (65# or 80#) with 190 lpm pump
EBL prom tuning
Rest of mods are in sig

Cam Choices:
1. GM-LT4 cam, 204/210, .476/.479, 1.6 rockers, 115 LSA
Very tuneable, but not aggressive enough?

2. GM-ZZ4 cam, 208/221, .474/.510, 1.5 rockers, 112 LSA
Good low/mid range torque. Other TBI guys are using this
with success. Low cost on ebay.

3. GM-LT4 Hot, 218/224, .492/.492, 1.5 rockers, 112 LSA
Is 224* exhaust duration too high for TBI tuning? Low cost on ebay.

4. Comp Cams 07-501-8, 212/218, .488/.495, 1.5 rockers, 112 LSA

5. Comp Cams 07-502-8, 218/224, .495/.503, 1.5 rockers, 112 LSA
This is very similar to the LT4 hot cam

6. Lunati 54755, 215/218, .489/.503, 1.5 rockers, 115 LSA
Designed for EFI applications. Seem like a real good cam, 115 lsa should make tuning easier.

7. Lunati 54779, 215/224, .489/.489, 1.5 rockers, 112 LSA
Designed for EFI applications. Nearly the same as LT4 Hot.

I'd like to use the LT4 hot (choice #3) or the Lunati 54779 (choice #7), but I'm a little unsure about the 224 exhaust duration. Is that too high for TBI tuning? If it is, then I'll probably go with the Lunati 54755 (choice #6). It has lower exhaust duration and the 115 lsa will make tuning easier.

Dewey, Fast355, BMmonte, BronYur, Shifty, RBob, and other experienced tuners, please post up with your thoughts.

Thanks

Fast355

iTrader: (2)

Its hard to beat the Crane that I had in my G20.

CraneCams

IIRC, you are well on your way to getting good at PROM tuning. You should have no problems with the tuning side of things. It looks like a pretty hard to tune stick, but it really isn't. It pulls good vacuum at idle (16 in/hg @ 700) so you should have no problem.

I also am a firm believer that you should stick with your current injectors. Bump the fuel pressure much higher though to get the fuel you need.

RBob

iTrader: (1)

I agree with your choices of #3 or #7. The LSA/LDA on 1 & 6 is too much. Another thing about LT1 cams is that the specs vary. It all depends upon the year and whether it is from a caddy, Y, B, or F body vehicle.

The cam Fast355 posted is similar to your choices. I didn't calc the LSA/LDA, so that value could make it a yea or nay.

RBob.

Mike1

iTrader: (2)

I've got #6 laying on a shelf here with hopes of putting it in a 350 when get funds for the motor. I got it from a buddy who ran it in a 350 and seemed to do well. He also ran NOS at the track and said it ran great. What would make this a bad choice? Why is the LSA bad? I hope to be able to build a strong running 350 and possibly putting a Whipple Charger on later for a little forced induction like Toxinz has on his.

Mike

RBob

iTrader: (1)

It isn't as much as it is a bad choice. It is that there are better choices. By spreading the LDA/LSA the overlap is reduced. It makes for a smoother idle and an easier to tune cam. The trade off is in the power the cam makes.

If I had it on the shelf I'd use it. If I had to purchase one, I'd go with less LDA/LSA.

RBob.

Fast355

iTrader: (2)

IIRC, the Crane that I used is on a 110 or 112* LSA. My NEW 350 uses the Ramjet/HT383 cam and it is on a 109* LSA. I love the way it pulls, I could easily spin the tires, towing something.

liquidh8

I agree with RBob.
BTW, I havea comp XFI cam in my vortec headed 350. PN#12-366-4, the 268XFI, duration is 268/280, @.050 is 224/231, lift w/1.6 rocker is .520/.515, LSA is 113 d. I am using a 1.5 rocker, and this is a hydro flat tappet, not a roller. I love the cam. I have the EBL, 3.73 gear, 2004r, and n2o. Putting a 2200 stall converter in this weekend, it needs it. the cam range is 2k - 6k. BTW, idles in gear @ 625 rpm smoothly. ( with the EBL)

Dewey316

I am with all of the other guys. For the most part. I would go with either of Lunati cams, They should both suit you pretty well for your 300fwhp goal. It looks like they both have the same intake lobe on them, the only diffrence is the exaust lobe.

I also think #4, with some 1.6 rockers would be a good choice, so long as your heads will take the lift. You want to be carefull going too big, seeing as how you are on the stock bottom end. Pushint the revs too far could prove to be a problem, especialy if you have a ridge from the years of wear on the cyl. wall. But I think either 4, 6, or 7 would be fine. Even the hot-cam would be alright, but that would be the MOST cam I would want to go with that motor.

DM91RS

I have had #1 in the car for 5 years. It or an LT1 would "do" if you had zero funds and it was free or dirt cheap.


I have #2 on the shelf to install in the upcoming 350. Now I think it would be a good 305 cam.


I now want #3 instead of #2 and think for the price that you cannot beat it. You seem to be very capable of tuning so I think that it would give you the most bang for the buck with your 3:73 rear gears.


The spec's that I have are listed as: LT4 HOT Cam, 218 / 228 Duration@ 0.050


On the injector's Rbob gave me the following example.

{Lets use the 300 HP:

300 * .5 BSFC = 150 # of fuel per hour. Divide by .85 for 85% duty cycle:

150 / .85 = 176 #/hr of injector. Two injectors is 88 #hr each.

To use the 61 #/hr Org/Blk's will need to raise the fuel pressure to 24 psi. Any increase in fuel pressure will also require a port injection fuel pump. Also, the 24 psi is based on a 300 HP engine, which you may or may not approach. I used that as it is the 1 HP per CI value. }

You make your own decisions about injector sizes. I went up to 61 pounders and installed a Walbro 190 and am at 18 psi and still having lean spots.

IIRC your RS does not have that high of mileage. SO..........it's gonna b fun

BMmonteSS

You also have to keep in mind cost, you may make a few more HP with the other cams but the HOT cam is going to be the cheapest of them all by a pretty good margin. I had a 216/226 cam with a 110 lobe sep and it was bit tricky to tune at idle and off idle because of the overlap, this was in a 350 so a 305 would be worse. I would stick with something in the 112-114 lsa area and give up the 5-10HP it's worth.


Of course you could go get that duntov 30/30 cam I've been hearing about, I hear it runs great with stock swirl port heads.

Cadillac

There you go complicating matters.

DM91RS

Which cam is that?

Oh yeah...it's the one with two 30 pound bags of

91RockS

Thanks for all the feedback guys, I really appreciate it. Although I like to keep costs down as much as the next guy, this is one of those items that I'm not going to skimp to save a few coins. Based on the feedback so far, I think most all of these cams will work out well, but I agree a few of the choices (like the LT4 hot) will want to be shifted in the 6000 rpm range, which may be pushing it for a stock bottom end. To be honest, I'm really leaning towards the Lunati 54755 (#6). I think this will be a good mix for street, strip, and tunability. Of course, it's the most expensive stick on the list! Fast355, I'm going to take a closer look at the Crane cam you suggested (hard to argue with success).


RBob, Can you explain why the Lunati 54755 (#6) will be harder to tune than the Lunati 54779 (#7). I thought it would be just the reverse since the 54755 has a higher LSA (less overlap) and less exhaust duration than the 54779.

Fast355

iTrader: (2)

The cam I suggested will pull hard to about 6,500 with a rev kit, properly matched springs, good flowing heads, headers, good intake, 454 TBI, proper fueling, and a built up bottem end.



He is probably saying that from a power stand-point. Manifold vacuum is less important with the EBL's Alpha N function.

RBob

iTrader: (1)

Not the tuning, it is how it will run the engine (this is as Fast355 mentioned). With cams in the 210 - 220 duration @ 50 there is no reason to go to a high LDA/LSA. Keeping the LDA/LSA in the 110-112 range will make it easy enough to tune. And, provide the response and power excepted.

RBob.

M1tch

what would be the best cam for a stock l03 engine but good for when i get heads in the future?

91RockS

Virtually any cam swap you do on a TBI will require chip tuning, so make DIY tuning higher on your priority list than the cam swap. Headers and cat back should also be done before a cam swap, along with intake improvements. With that said, a used LT1 cam from mid 90's camaro/firebird is a very good, low cost, easy to tune cam for a beginner. It's certainly not a high performance cam, but definitely a huge improvement from the factory peanut.

weberflorida

iTrader: (2)

Rrob,

Is the EBL the S H I T? Just wondering? I am going to get into tuning my combo when I get back from Iraq. I have no prior tuning exp other than what I have been reading. Also I have a Stock L98 with TBI and 350 Injectors, Headers and three inch exhaust all the way back. I have never run it at the track or ever run it on a dyno. Haven't even really broke in the motor. Got a chip from TBI chips and it seems to work good just wanted to get into it myself and tweek my own setup.

Thanks

Bill

RBob

iTrader: (1)

I think it is. For a TBI system you can't get a better setup. I have it on two of my cars, and it will soon be on a third. For other folks opinions there are a couple of active threads on the DIY_PROM board. WebSite was updated yesterday with the new WUD screen shots.

RBob.

mnorton

Can you really fit 1.94/1.6 valves in those 081 heads?

Dominic Sorresso

91Rock,

I had cam #4(HR) in my 350 for several years. You need to remember that you're working on a 305. Less cubes, less cam. The 212/218 was very nice with lots of torque. Using TFS heads, the power peak was at 4800-5k. Pulled 275hp at the rear wheels with 347rwtq. Idled very nicely. I have since gone to a cam with a 108LSA.

91RockS

Good catch. The valves are 1.94/1.5. Original post edited to correct.

mnorton

That's more like it!

My S/R Heads have the same size valves.

You can get also under-cut valve stems for a little better low lift flow.

I'd pick number 4 from your list of cams for a 305. It has about the same durations as my cam, but more lift.

214 (270) / 220 (276) 112 deg. 452/465

Lift with (1.52 rockers): 0.458"/0.471"

91RockS

Thanks for the advice. I agree that #4 is looking like a good choice. Fast355 recently posted 305 dyno results using a LT1 cam with 1.6 rockers. Something like 258 rwhp. With 1.6 rockers, the LT1 cam has almost the same lift as #4, but with less duration. I've got an LT1 cam and 1.6 roller rockers sitting on the shelf right now. Maybe I should save the $$ and just go that route!

M1tch

i dont want an LT1 cam, i want a little hotter. I'm buying the PROM-inator next week so i understand the tuning part
----------
He swapped heads too right?

DM91RS

IIRC the heads on the engine were 081's. The same as 91RockS is installing but FAST355's were with stock intake valve size and not ported.

91RockS

Your're exactly right DM. Fast355's heads were stock 081's. Mine are ported.

escort_ford84

I am using that duntov 30/30 in my 88 Formula and like it.

BMmonteSS

Ohh god, not another one.

DM91RS

LOL

BMmonteSS

Escort, I don't mean to give you a hard time you seem to be asking some very intelligent questions in other threads. If you do a search for the duntov 30/30 cam you'll see where another ,shall we say.......... interesting, board member decided to school us on how that cam was perfect for his bone stock LO3, and how he was able to tune it without any experience in just a week or two. Funny stuff

91RockS

Is it groundhog day?

escort_ford84

I figure my car with that camshaft is about 1 second quicker. My car ran stock a 17.3 @ 79 MPH. the 60 foot was 2.3. After burning a few chips for the thing i found the stock camshaft was a PINGING S.O.B!!! where is ran a 17.0 @ 80 MPH.I haven't had it to the track yet after my cam swap, but my MPH is around 90 now. For some dumb reason my car takes off harder now. I remember when purchasing the cam hear how my car will be "undrivable". No, its not undrivable. I put 200 miles a week on it or more. And you know, the funny thing is the first chip i made was after i installed the cam and it started and ran fine. Buddy of mine told me the stock tunning was better than anything i could come up with, so we put the stock (AXKW) back in. To his amazement, we never made it to the gas station 100 feet from my driveway. in went my chip and a new set of plugs got it back to my driveway. He hasn't commented about my inability to tune a engine anymore. Its just i have about half a map to work with. I have installed an intake the other day, waiting for a reply on thermostat temp. It used to REALLY bother me on how i didn't know what i was doing, that is why i keep my stock prom safe.

jax1-2

would the crane cam mentioned work with a vortec 58cc head setup well? i am kindof new to this cam thing we use to get them into my dads shop with the cam already in.

escort_ford84

I have used a Crane cam in my stock 87 350 IROC and was happy with it.
Part # 100082
Specs are 226/226, .470/.470, 106 lobe sep, 101 intake centerline.
If you dont like a Radical Idling engine, dont use it.

escort_ford84

My goal is to trap at what the 1967 Z-28 did in 1967 since thats the camshaft im running, the article is now gone. I believe it was 14.8 @ 96 MPH. that car was equipt with 3.73 posi and a stick, the 6 MPH i may be able to get with other mods.