Just found out I have a major bottleneck going on in my 383 stroker motor. I only drive the car about 10 miles a week and that is if it's nice outside...car pulled 420rwhp three years ago with the heads that are on it. This past summer I got my new stroker motor and gears at the same time and of course the car feels much stonger (partly due to the torque of the stroker...but probably mostly due to the gears) Used Ed Wright for programing, but recently found a problem with the fuel system so decided to get a custom tune and dyno the same day and also add my new 90mm set-up on as well. Car only pulled 445rwhp and 440rwtq...I know that the gears will through the dyno off abit, but was expecting something closer to 490rwhp with my "383".
The current heads are about 3 years old port and polished Ls1 heads with 2.02 int. and 1.57 ext. I believe they flow about 260??? But honestly not sure since it was awhile ago. Engine should be around 11:1 CR.

It must be the heads since everything else flows incredible well. Here are the other major mods:

Vortex Rammer
Ported Z06 MAF
Custom 90mm TB
Fast 90mm Intake
***Stage II ported LS1 heads
Kooks 1 7/8" headers with X-Pipe and no cats
Corsa Indys

Questions:
Should I get some LS6 heads? If so then who's flow the best? How much HP could I pick up on the additional CR? Should I wait for the AFR 225? When are they expected to come out?

All comments welcome

Thanks,
Rick

 

Go here http://www.airflowresearch.com/ for AFR info. Click on LS1 on left side. No info on availability of 225's. :steering:

 

Thanks, that brings up a question though...it says the 225's are for engine 396 and up...does this mean that they cannot be used on the stock bore of the LSx engine?

 

Rick you sure have the intake stuff and the exhaust stuff it would seem the only bottle neck you could have would be heads, a good set of ls6 heads would flow well over 300 and the 2.05/1.60 would be great for the 382 the bigger valves have less VE in less than about a 427--I would run it by some of the tuners and get a good complimentary cam as well--Vince just put some ARE 5.3 liter heads on his 382 and backed it with a big cam like a 240/244/608/612--114--he'll be posting track times and giving impressions this week it may be a good example for you as you have very similar setups--Nick would be good guy to talk to about it as well---also remember you picked up 25rw with the addition of about that many cubes and you lost about 10rw on your gears--so you picked up 35rw with less than that many cubes--cam and heads and you will be near 490--sounds like a fun project look forward to the post--

 

Thanks Bill :cheers: My tuner (More Performance) is great. Owner Mike Osh build engines for Winston Cup for 12 years so he is very solid...he is recommending ported LS6 heads, but I always like to ask many of the experts on the forum (including yourself :cheers: ) these questions. So I can learn as well and keep him honest in the mean time :yesnod:

The cam I'm running is pretty strong right now 236/238 .610 and 112lsa. Do you think I should have gone bigger? Who would you recommend getting my heads from? If you don't want to say online send me an IM. Do you think I should it's worth it to wait for the AFR heads?

BTW: Nick has been of great help and I do trust his jugment as well...unfortunatley he does not machine his own heads...yet
;)

 

It would be worth a call to Tony Mamo at AFR to get the straight story on the 225 fit on your 383 stroker. Since the 205 heads are 3 weeks away at best, I don't think you'd be seeing the 225s inside of 2-1/2 to 3 months. I'm waiting for the 205s myself. Everything else you're doing is way beyond my pay grade. Good Luck with your project! Best,

mtv :thumbs:

 

I have a similar motor as you do. For comparison sake, my car made 430 with stock ls1 heads, stock intake and stock TB. It made around 480 with ported ls6 heads, stock intake and stock TB.

What size cam do you have? Did you get numbers before the FAST intake and TB?

Your numbers are low but I havent seen anyone hit 490-500 yet with one of the Lunati strokers. I plan to do it within 2 weeks on mine. ;)

I am pretty sure heads are a major restriction. A good set of ported LS6 heads will cost you over $3000 though.



[Modified by kumar75150, 12:23 AM 4/12/2004]

 

Sorry I just read your cam specs. Thats about the average size I see for a 383. You could go bigger and pick up some power if you want though.

I'd think ported LS6 heads would be the best bet. Absolute Speed, MTI, and Cartek and some of the first people that come to mind as far as head porters go.

I'd guess and say you could pick up an easy 30hp from heads and an easy 10hp from a bigger cam and possibly more from each.

485 would be a good strong number.


[Modified by kumar75150, 12:24 AM 4/12/2004]