transsam

iTrader: (5)

I have a car with a 384 LS1 engine that must have cats. The best I can run for exhaust is shorty headers through cats. Would moving from a relatively stock intake system to a FAST manifold with larger lid, MAF and TB be worth the investment even with the massive restriction of my available exhaust?

99Bluz28

iTrader: (35)

I'd stick with a LS6 intake and ported TB, and put that money into having the heads ported and milled, or milled AFR 205s/210s.

LS1-450

iTrader: (33)

IMO, it's not worth the investment. Better to spend the $ to find a way to install long tube headers w/ your CATS. Sounds like there's an issue w/ body interference or something. It's not that shorties are restrictive, it's basically that the primaries are not long enough to seperate exhaust from one cylinder to an adjacent cylinders' combustion chamber.

...then rework the intake side as you wish.

transsam

iTrader: (5)

Thanks for the info guys. The heads are good on the car. It is a built 384 stroker. The goal is actually to pass emissions with CARB legal parts. With the amount of money that an intake system would cost me, I think it would be best to put it toward low compression heads and an STS with like 4-5 lbs of boost.