New to board, and new to Third Gen upgrading as well. (Old school muscle-car guy). Anyway, I have a stock '91 Firebird 305 TBI. Love the car and just am planning mild upgrades. Here's what's I will be doing, just looking for any constructive criticism or alternate plans. Thanks!

Remove A.I.R. system (mostly for improved access and looks)

Dynomax 2 1/2" or Jeg's 3" cat-back system (have both), Jegs is poorly constructed and missing hangers, Dynomax looks like a slam-dunk to install.

swap 2.73 axle for 3.08 (I have the 3.08 posi out of my '85 Berlinetta)

Buick GN fan switch, Redline watter wetter or like-type product with 180* balanced valve type (Milodon, etc) thermostat

shift kit and trans cooler for the 700r4

Steering brace

Poly sway bar and end-link bushings

235-60x15 tires to replace the 215-65's currently on car (stock 15x7 aluminum rims)

open element air cleaner

fuel injector spacer

4-8* initial timing

Swap swirl-port heads for a set of fresh 416-casting 305 H.O. heads (I already have the heads)

I just want a slightly better performing, cooler running, and better handling vehicle. My car has the "soft-ride" suspension option, so I'm thinking maybe I ought to go with the Trans Am front coils as well.

Car has T-tops, so I may also be looking at sub-frame connectors if I can find some that don't interfere with the exhaust and don't cost an arm and a leg!

These mods are what will be happening immediately, down the road I may look at more gearing, better shocks/struts, and more poly bushings.

 

Move the sub frame connectors up towards the top of your list. You don't have to waste money on a pre-fab'd kit, just get a few lengths of rectangular steel tubing and cut/weld your own. I did mine for under $40.

 

I'd put headers/catback and sub frame connectors up near the top of that list. You'll get the most benefit, initially, from those two.

 

Thanks! I will be doing the subframe connectors, what I listed in my original post was what I had on hand right now. I also have headers and y-pipe from my '85 which will be going on eventually. Right now there is nothing after the cat, so I need to address that first. Do the rest of my mods sound reasonable?

 

If the 416's are just sitting around, why not look into some DIY port work, make them flow decent.

Maybe consider a mild cam upgrade (LT1 cam would be a decent upgrade). Look over the LT1 Cam sticky in the TBI boards, if you haven't already. Between this and better flowing heads, that's the next largest seat-of-the-pants improvement.

The rest looks pretty reasonable.

 

Just remember that's illegal on a street car in all 50 states, regardless of if your area does emissions checks or not. And if your area does do emissions checks, you might not pass the test.

For more ideas, see the Ultimate TBI tech articles on this website, and search the TBI forum.