Ok, I want a sleeper exhaust. Right now, i am using the stock manifolds off of my old Lo3 tbi 305 that now sits in the garage. Ported L98 manifolds seem like my answer. What all is involved in porting exhaust manifolds, how much does it cost, and how much power would I give up compared to POS headers like edelbrocks? Is porting the manifold worth it? Like I have said in other posts, I want to remain stock looking, but the car now feels and sounds like it is is being held back by what is on the car now.

 

Ported L98 manifolds should give you decent performance. The stock TBI manifolds I'm pretty sure have 1 7/8 outlets while the L98's outlets are 2 1/4

 

To get the best flow for the most money I would have them extrude-honed, I would guess their website is www.extrude-honed.com, I could be wrong though. They will flow like crazy, but it is expensive.

nick

 

I'd say its probably worth it, plus adding L98 exhaust is a nice cheap mod for TBI car. Since the manifolds are log style, you probably wont be able to port far, but smoothing the transitions and removing flash can't hurt. BTW, I plan on doing the same mod, I bought manifolds for $13, and a nice y-pipe for $45, beats a couple hundred at least for headers.

 

Maybe look into using LT1 manifolds. It will still be a sleeper look but they had to be designed to flow more since they are on a 285HP engine and not a 240HP one.