Kalibar12

so ive got an lt1 block and supposed lt1 heads. when i finally get round to working on this engine, i plan to stroke it and try to get around 500 crank horses. my question is, are the lt1 heads good for this or should i get differnt ones?

Thirdgen89GTA

iTrader: (5)

Are we talking LT1 as in Gen-2 SBC (1992-1997 in Y, F, and B-body cars), or the original LT-1 of the 70s?

In any case, I doubt EITHER the 70's LT-1 heads or the later Gen 2 sbc heads can net 500hp without port work. Best i've ever heard of was the a few custom big cams making near 370rwhp with stock heads and supporting mods. Thats at the upper limit with horrible street manners.

DeuceNC

I'd say it would be possible with the right internals, but would probably be more expensive than what its really worth. I'd go for an LT4 conversion if I were building it.

Thirdgen89GTA

iTrader: (5)

Every one RAVES about the LT4 conversion but its not worth the money unless you really want to have them special LT4 valve covers.

You want a cheap, proven heads/cam package? Lloyd Elliot sells it. Guys run his stuff all the time. LT4 heads don't flow all that much better than LT1 heads. The Lloyd Elliot heads will come prepped for a big cam too, so that saves the money of buying the springs/locks/retainers to make a LT1 or LT4 head handle a large cam.


There is also Advanced induction, AFR, etc....other aftermarket heads flow more as cast and have greater porting potential.

Kalibar12

its a gen II. atleast the block is. need to double check the heads. i figured i would have to go with AFRs or something, but my step dad keeps swearin up and down that the lt1 heads will work fine. in fact he just said its not worth porting heads because its easier and chaeper to buy new heads. so what do yall think i should do? port the lt1s or buy new heads?

Thirdgen89GTA

iTrader: (5)

There is no if/and about LT1 heads. Regular SBC heads won't work, and vice versa without modification.

my advice, go to http://www.mortec.com/castnum.htm and search the page for casting #'s that match your head. The casting #'s can be found by the springs. They can be iron or aluminum. Iron is from a B-body (Caprice, Roadmaster, Impala.....), Aluminum is from F or Y body (Vette/Camaro/Firebird)


If you are on a budget you can make plenty of power with the stock heads. You mention 500hp, have you ever ACTUALLY ridden in a car that makes near 500hp, even at the crank? Thats enough to propel an F-body well into the 11's if you can drive it. If not, just toss a CC503, Hot-cam, or something similar in there and you'll get PLENTY of power.

I'm trapping easy 100+ with my B-body swap. And thats just the 260hp iron headed baby cam motor. I pulled 102.xx all day long while the PCM was pulling 5* of knock retard because of false knock generated by an exhaust leak at one of the header primaries. And the DA was 95%.

If you don't know what you have i'd find out fast before you start spending $$$. And if all you have is the short block, and heads, then you have ALOT of money left to be spending to get it running. I'd estimate about $1000 left to spend at the minimum. Intake, opti, harness, pcm, sensors, accesories, etc.....the list goes on.

Kalibar12

i meant 500 at the crank. and no, i havent ever ridden in a car with 500hp... never had the chance :/. im aware that i need alot more than just an engine, i plan on kinda taking my time with this car. wanna do things right from the get go. i have the intake for it but its missing the fuel injectors and rails so i figured id just carb it anyhow.

Thirdgen89GTA

iTrader: (5)

Carb is fine, but I'd just go with stock heads for now and a mild cam around 220* duration. The stock heads can support that no problem, and with the right bolt-ons thats enough for 320-350rwhp.

This is a video of my GTA at the strip. Stock B-body LT1 swap (260hp), iron heads, and the baby cam. Mods are 2055 shorty heads, CAI, SLP 2otL cat-back. Was pulling 13.593 @ 102.37mph, adjusted DA time would be about 13.3 @ 104mph. PCM was also pulling 5* of spark advance due to false knock from a header leak.

http://www.youtube.com/watch?v=L9W0dHn1Gl8

Kalibar12

sounds about like what i had originally planned, 400hp at the crank. was told this was an everyday kinda number and decided to shoot for 500hp. gonna do somethin, mind as well do it big right? could always do some modifications and slap on a turbo later right? also, what size carb would i want to be using with these heads and a mild cam?(holley 0-4778?)

ive also been told 3.55 would be good gears to go with for street application. is this true?