LT1 upgrade, Which way???

[Guest Firebirdlt1]

I need some input on which is the better way to go with my 94 formula. I was planning to install an 8 psi. prochrager system w/twin intercoolers. That would run me about $4000. But I was looking though a summit racing book and saw an LT4 upgrade kit which includes: LT4 cly heads, LT4 intake mainifold, LT4 hot cam, 1.6:1 rollor rockers, and all gaskets for about $2,300 They say it proven for 425+ Hp. Anyone done this? I'm just looking for some opinions.

[SamZman]

I went the blower way first, but mainly because I got a good deal on it. Knowing what I know now and hearing all the stories of people burning holes in pistons w/ superchargers I would do it differently if I had to start over.. Even though I've gone ~40K miles trouble free w/ the supercharger there is a definite possibility that you would not be so fortunate..

 

If you do plan to go the heads and cam route (which I'd recommend)you might as well do it right. And by that I mean getting some ported LT1 or LT4 heads and a bigger cam such as a cc306.. you may wanna check out racenet.net (http://www.lt1f-body.racenet.net/valvetrain.php). Joe and Josh have both done this so they may help more..

[Guest stevil]

I agree, don't just convert to an LT4. Spend $1500-$2K on a good set of heads, get a bigger cam, as well as alot of other misc stuff like rockers. Should be around $2500 or so. You can make more power for about the same price.

[MrMeanGreen]

Moving to Tech...

[ORourke]

For what you spend on the LT4 conversion you could get a better flowing set of ported LT1 heads and a cam of you choice. 425hp is a flywheel number, and even that is very optimistic. Check out www.combinationmotorsports.com for heads/cam packages, they're very competetitive price-wise with the LT4 conversion and will make a lot more power. I've also heard good things about Phil from www.advancedinduction.com.

 

If spending 4k on a blower setup is an option I'd just get heads/cam and then spray it. LT1's don't handle boost too well with the stock hypereutic pistons and 10.5:1 compression. Some people get lucky, but some people have to rebuild after a few thousand miles.

[smokin5s]

Originally posted by SamZman:

I went the blower way first, but mainly because I got a good deal on it. Knowing what I know now and hearing all the stories of people burning holes in pistons w/ superchargers I would do it differently if I had to start over.. Even though I've gone ~40K miles trouble free w/ the supercharger there is a definite possibility that you would not be so fortunate..

 

If you do plan to go the heads and cam route (which I'd recommend)you might as well do it right. And by that I mean getting some ported LT1 or LT4 heads and a bigger cam such as a cc306.. you may wanna check out racenet.net (http://www.lt1f-body.racenet.net/valvetrain.php). Joe and Josh have both done this so they may help more..

I love my CC306 setup.... deffiantely go that route.. although having a blower is pretty cool. how many miles do you have on your car? I know that having a blower is hard on the stock bottom end, but doesn't require you to tear the motor apart. If you get your heads ported, MAKE SURE to go somewhere that they know what they are doing... I had to tear my heads off 3 times because the place I got my heads ported at didn't account for the increased lift on my cam. But, LT4 heads are deffinately better flowing heads even if you don't port them, but I would stay away from the LT4 hotcam. I agree that 425 is quite optomistic for that small of a cam. but that package isn't bad since it includes the rockers and such.. one other thing to keep in mind, an LT4 intake is only a powder coated port matched LT1 intake, so don't bother spending the money, just have yours ported. honestly, I think you'd be very happy with ported heads, 1.6 rockers and a CC306 cam.... another good thing, the 306 cam is N2O friendly If you want to discuss it further, hit me up on IM or something, I'd be more than happy to discuss with you about it.

[Guest Firebirdlt1]

Thanks for the help guys. I'll most likely go for the ported LT4 heads and my current intake matched to fit. along with the 1.6 rockers and cam. Is the CC306 streetable? I want to drive this everyday, or when weather permits. know of any good places to get the ECU reprogramed?

[SamZman]

Originally posted by Firebirdlt1:

Thanks for the help guys. I'll most likely go for the ported LT4 heads and my current intake matched to fit. along with the 1.6 rockers and cam. Is the CC306 streetable? I want to drive this everyday, or when weather permits. know of any good places to get the ECU reprogramed?

It's not necessary to go w/ LT4 heads. Your ported LT1's will work quite well. You'll also need to get an LT4 intake if you wish to use LT4 heads.. I'd save the money and get your heads ported and factory intake port match. I have a friend running 11.7's w/ stock ported heads..

 

That cam is a streetable cam and I have a friend who could throw a program on it for ya for pretty cheap..

 

I'd really recommend just calling combination as slowgreencar suggests. They are really friendly and helpful guys, and can give you better advice as well as prices..

[Nitrousbird]

I personally wouldn't ever waste my money on LT4 heads unless I could get them used. For the price of them, you can spend a couple hundred bucks for and get yourself a set of AFR's.

 

My roomates car, back when it was N/A, made 330RWHP (6-speed car) w/ that LT4 package (unported heads/intake, LT4 Hot Crap cam, 1.6 rockers). That was with mail order tuning, RK Sport 1 3/4" shortys, high-flow catted y-pipe, Borla, 58mm TB (but intake was not port matched for it), and stock SS intake. Car had a header leak and could have used some more tuning, but at most it would have maybe made 345 RWHP running perfectly.

 

If I were to do it again, I'd definately go forced induction. It's not that hard to pull a motor. Do a budget 355 w/ a blower, or a turbo. The turbo will cost a bit more, but you get to offset a bit of that cost because you would most likely buy some good headers w/ a supercharger, where you of course you don't w/ a turbo. And don't forget, buying used can save you a large fortune!

 

Either way, that's how I do it if I had the funds to do it over again. Not to say my current setup isn't fun (and goes down the 1/4 far quicker than any local rotary tongue.gif ).

 

Screw it, make an N/A monster. 401 LT1 w/ Hogan intake, Arao Dominion 32 valve heads (fully worked over), 8 primary custom headers, MoTec sequential fire PCM, solid roller, etc. We won't discuss the price of such a project...........

[SamZman]

Originally posted by YMN:

although having a blower is pretty cool. how many miles do you have on your car?

I said above I've put 40K miles on my car w/ the blower.. I'd have to sit around and think about it, but I think I was still in the 70K's when I put it on and am ~110's now.. to be honest I cant remember how many miles are on it right now..

[Guest stevil]

Originally posted by Nitrousbird:

345 RWHP

Yep. But a great set of ported LT1s with a nice cam, shorties, stock exhust with a cutout, and a few other little things can make 410+ rwhp at the wheels. Click on that Advanced Induction link slowgreencar posted above and check out the dyno numbers.

[smokin5s]

Originally posted by Firebirdlt1:

Thanks for the help guys. I'll most likely go for the ported LT4 heads and my current intake matched to fit. along with the 1.6 rockers and cam. Is the CC306 streetable? I want to drive this everyday, or when weather permits. know of any good places to get the ECU reprogramed?

with the proper tunning it can be streetable... it's just getting there with the tuning that's the hard part. I've been fighting with my tuning for months now. (I am a total amerature with tuning though) It's totally streetable now, but it's a gas hog, and not tuned too well cause it's pulling all sorts of timing on the top end. If you have a '95, I can help ya out with tuning, if it's an earlier year, there are a few guys on COFBA that might be able to help ya out there. check out www.cofba.org

[Guest Firebirdlt1]

You guys have been a great help. I'll definetly go the N/A route. I'll check out the links you suggested. If I can get to 400 rwhp, for under $3000 by doing it myself and using my current intake and heads (just porting and such)plus other mods. ex. headers etc. I'll be real happy. I didn't know the LT1 could make that kinda power without some postive manifold pressure. After I do all this I better save up for a new rearend and tranny smile.gif

 

Thanks.

[Guest mudbutt]

While the subject is open, what would the stock rods be good for powerwise, in a forced induction application?

[SamZman]

Originally posted by Stinky Pete:

While the subject is open, what would the stock rods be good for powerwise, in a forced induction application?

I believe they are rated for 600flywhp, and I know of people runnin in the 500's at the wheels. Though I think running in the mid-high 500's for very long may be pressing your luck..

[ZYUL8TR]

Go to Performance Research, ask for Mike Phillips. Get your stock heads ported and bigger valves installed (they did mine and they perform extremely well). Have them set them up for approx. .610 lift and use Comp Cams Pro Magnum 1.6 rockers. Install the CC306. SamZmans' friend has Tunercat and has a copy of my program which he installed in my car for the CC306. I ran an 11.79 @ 115 (ported heads, cc306, 4.10 gear, th350 3800 stall, longtubes, h-pipe and true duals, 30lb injectors, stock bottom end) this past Friday at Super Chevy. I drive it quite often. Do the same and yours will perform well.

[smokin5s]

Originally posted by ZYUL8TR:

Go to Performance Research, ask for Mike Phillips. Get your stock heads ported and bigger valves installed (they did mine and they perform extremely well). Have them set them up for approx. .610 lift and use Comp Cams Pro Magnum 1.6 rockers. Install the CC306. SamZmans' friend has Tunercat and has a copy of my program which he installed in my car for the CC306. I ran an 11.79 @ 115 (ported heads, cc306, 4.10 gear, th350 3800 stall, longtubes, h-pipe and true duals, 30lb injectors, stock bottom end) this past Friday at Super Chevy. I drive it quite often. Do the same and yours will perform well.

Glen, any chance I can get a copy of that program? I can't get mine tuned right..... (getting allot of knock and pulling timing on the top end.)

[ZYUL8TR]

Originally posted by YMN:

Glen, any chance I can get a copy of that program? I can't get mine tuned right..... (getting allot of knock and pulling timing on the top end.)

SamZman has Judd's phone number. PM Sam and see if he can get in touch with him for you.

[smokin5s]

Originally posted by ZYUL8TR:

SamZman has Judd's phone number. PM Sam and see if he can get in touch with him for you.

awsome, thanks man! Sam, if you see this...

MMMMMAAAAAAAAAAIIIIIIIIIILLLLLLLLLLLl