So I need some help on how to build my 383 LS1. The goals for the engine is to make 500hp and operate in the 2000-7000rpm range. I will be using 241 heads, 10:1 compression, 1 3/4" to 1 7/8" stepped headers. Engine will be using a carburetor and will be pushing a 3000 pound car. The car will have an automatic transmission with overdrive and a 2500 stall. A 4.10-4.30 rear gear. Can anyone recommend a cam with a rough idle and an intake manifold to use for the carburetor? I'm not used to carbureted 383 LS1's.

Thanks!

 

first, why are you going carburated? 500fwhp or rwhp?

 

What size bore?

 

it would be nice to get 500rwhp but not being picky 500hp is a lot of power regardless. the engine is going in my 1970 trans am and want to keep it simple since I have no smog. I also want to keep the shaker hood (my favorite part of the trans am). I already have the long block but dont have the PCM, fuel pump, injectors, harness, etc. so i figured carbureted would be cheaper and easier. Bore size would be 3.935? Isn't a 383 LS1 stock bore with a 4" stoke?

 

your not gonna make 500 to the wheels with 241 heads. I have a 383 in my 79 Camaro with a Comp Cams 287 grind with AFR heads. It might make 480/490 rwhp.

 

your car made 480-490rwhp? my alternative was to sell the ls1 long block, get a LQ9 408 with L92 heads but im just shooting for low 11's in this street car. would a ms3 work well to the 7000rpm or would the extra 37 cubes affect the stated 2300-6800 rpm range?

 

For 500 RWHP, you are way closer with an LQ9 408 than a 383 LS1. Especially for reliability.

 

Here's the 500 HP motor in my 72 Camaro that I just sold a couple of months ago. All Forged Flat top with big Comp, Barry Grant, Dart Pro 1, MSD Billet. It was a fun ride.

 

Powerwise you will be handicapping the engine with (relatively) crappy 241 heads and a (relatively) low 10.1 compression ratio. The extra cubes probably won't add a whole lot of top end horsepower, although the torque curve should look better.

 

383 ls1 bore 3.905 11:1 cr prc227 ms4 cam fast 90/90 will make 500rwhp i know that!!

 

are you going to use the edelbrock intake ignition kit?241 aren't really bad ,but try to find some 243s.get a custom cam from Patrick-G .I have never seen a 500hp sbc with a dual plane intake.I have one on my 427 sbc.

 

i'm going for the 10.1 compression to run 91 octane and not race gas. compressions more crucial when you don't have knock sensors. do you guys think the engine should make 500fwhp?

 

yea im going to use the 6010 msd box.

 

A factory stock LS2 is at 10.9 and will run on 91. Any tuner should be able to work around detonation. I would stay closer to 11:1 and at least run 243s or get the 241s ported. IMO a 383 with a set of PRC LS6 heads and an MS3 cam on a 112LSA would make a killer street engine. Would probably hit your goals.

What do you have already?

 

i have the long block and 241 heads. the long block i bought was from a 98 z28 with 100k miles. it came with a new alternator, water pump, and coils for $1000. im not sure if the engine has an LS6 cam in it already since the guy had yellow springs on the heads (LS6 springs if im correct). i found the 241 heads from a 2004 gto with only 17,000 miles on them for $150. I need to buy the rotating assembly.

 

send your 241's to someone like ai and have them ported and then have a cam spec'd for your setup and im sure it will make very good power.

 

You are throwing away a lot of hp using those heads...

 

IMO, I would get a set of l92's which are relatively cheap. But the matching edelbrock intake, use the MSD ignition system.. You can make 500 pretty easy, with lower compression though you will need to have a fairly aggressive cam. I would lean towards the 11:1 side on compression, still pump gas friendly but will make a bit more power.

 

port the heads for more flow and mill them for the compression bump....like said earlier....find some 243's if its in the budget...

 

l92 heads will not fit ls1 5.7L bore!! with my experience you cant go cheap on the heads if you want good results 241 heads will be good for 380-400hp 243 will be in the 400-420 stock heads unported some people will dyno a little more and some a little less 6 speed trans will dyno more then auto also why are you going cab you can get a harness and computer for about 350 fuel injection is the way to go!!