ploy22

Getting a new motor built and leaving the factory exhaust. I'm getting heads, cam and high comp pistons, what is the most anyone has gotten outta the factory exhaust?

Werks

I've run a little over 630 rwhp out of a N/A engine through the stock npp exhaust.

VetteVinnie

No headers?

I assume the OP is talking about stock manifolds, cats, etc., all the way to the catback.

ploy22

I'm talking manifolds back, 100% stock

Coach62

Why? headers are one of the best bang for the buck hp increases. Sorry but it makes no sense.

Adam_W

Headers won't pass smog in California unless someone is looking the other way. Those who want to play by the rules are limited in their choice of performance mods. Hope that makes sense.

VetteVinnie

But he's in North Carolina.

pkincy

Whatever his reasons, those of us in Kalifornia are interested in the thread.

ploy22

It's a money issue. I can add headers later, but want the motor built now while it's apart

jtjohn1

Mine is at 545RWHP with a fully stock exhaust and a very mild cam (Take off of the Torquer 116 just cut to 114) The shop that tuned it tuned it conservatively and said it could easily push over 550RWHP.

Got the WCCH Stage 2 head work, milled, the cam and a CAI.

50 4Ever

I live in CA and had to get my Z06 smogged 6 months ago. I was putting out 545 rwhp (the same rwhp as a stock ZR1 on this dyno). I removed my headers and burned out high flow cats and put the stock manifolds and cats back on. I also changed cams, I got the smog legal LS7 cam from Synergy Motorsports. I now put out 525 rwhp. Other mods left alone are CAI, WCCH Stage 2 heads and muffler mod.

I would imagine 550 rwhp is doable.

pkincy

Sounds like a Kalifornia friendly build.

My other experience is that the single most destructive mod to the good NVH of a OEM stock vehicle is the addition of headers, shorty or LTs. Yes, a huge cam can give driveability issues but I have modded a lot of cars and the addition of headers seems to be the biggest culprit in noise and vibration and heat additons.

I suppose my Hooker shorty's on my C4 383 LT1/4 with stock heat shields is a bit of an exception but the shorties on my 383 Camaro and the LTs on my various LS1/2 cars really took the car from being a comfortable street car to something that was maybe great but was no longer as useful as a street car.

dcamick

538 WHP similar setup!

Frans96ss

thats seems a tad high with stock manifolds... What kind of dyno?

Unreal

Talk to Funkybird. He is at ~550-560 rwhp on stock manifolds. WCCH heads, Big cam, etc.

smellya

530rwhp with full exhaust. Small smog Cali friendly cam. Forged motor, ARE stage 2 dry sump. As soon as I get my tranny and clutch. I have a burns stainless axel back exhaust.