Ok, I've done multiple searches and unfortunatly cant find any answer to my question. I am buying an '89 L98 with TPI next month and it has a hand ported/polished plenum, hand ported runners, and hand ported intake, also included is a custom prom. Everything else is stock on the motor and exhaust. I know factory specs are 230hp, but how much gain is made from those mods? Im thinking (hoping) about 10-20 all together. I will also do the Tb bypass and gut the air boxes with K&N filters or throw on a K&N cone filter. Anyhow, just a curious bug that has gotten ahold of me to find out how much more power I will be making over my current LO3.

 

I would say you're in the ballpark. But remember, that is bhp, not rwhp. You can always get rid of the EGR which degrades the efficiency of combustion in the combustion chamber to get out a few more numbers. When exhaust gas recirculates into the CC, it take up space.

 

Oh I know thats fwhp not whp, but like I mentioned, I just couldn't find any numbers on those things. Now I have a little more peace of mind knowing where I am starting from with this new motor. And I also know two other things, using a .83 multiplier gets me in the ballpark for whp (assuming a 17% drivetrain loss on an auto) and Im that much closer to achieving my goal of matching or exceding the performance of my last Camaro (stock 96 Z28 auto) Thanks for the insight, any others willing to confirm/deny this about where I will stand for BHP:250