I just picked up a 86 IROC-Z, 305 TPI, auto, 3.23 posi. I'm taking it off the road for the winter soon, so I figure fall is the best time to work on it. Anyways, what sort of mods should I consider? I'm looking to improve mainly the accelleration, not so much top end, being that on the crowded New York streets I'll never top the car out anyway.

I've figured I'd start with K&N's, hi-flo cat, cat-back exhaust, headers. On the exhaust, should I go with 3" or 2.5"? Who makes street legal headers? Other suggestions?

 

headers and cat-back are definately first. It really helped to wake mine up.

Hodge

 

i think 3" would be a little too much for the 305's, but if you're planning to do some heavy modding then the 3" would be fine. as for emissions legal headers theres a bunch out there, i think the popular choice on this board would be hooker, best bang for the buck, or if you've got the money then SLP would be the way to go for sure. they both have models that are emissions legal. take a look on summitracing.com, jegs.com, or slponline.com to check on more info for these headers

 

The biggest problem with your 86 is the cam. In terms of bang for the buck, the peanut cam has got to go.
The best beginner plan would be something like swapping the cam and porting the plenum and intake base while you're in there. Headers and full exhaust would be next in line. Etc, etc.

 

I would Port the plenum, Buy a TPIS or Edelbrock intake manifold, get some after market runners, Get a nice beefy cam for the car, get Some 1 & 5/8 headers, a 3" Cat back is most definatly not to much flow for our 305's, Your Choice of muffler.

OR for the price of the intake manifold + runners, I would invest in a Stealth ram unless you want to be legal.

Your car will breath like a dream.

Then its on to the bigger stuff Like heads etc.