I have a 91 camaro rs. stock 305 tbi. t-5 trans. The motor has 192,xxx miles but run great. Although it does run great, i know that it's weak and been through alot. Im considering a rebuild of the motor and want to keep the same block, heads and all the guts. Brand new it had about 170 hp, 190 tq. Can I add power with a rebuild? maybe mod the heads or change the cam? and if so, will it mess with the cpu? What about the trans? thanks.

 

I'm no expert, but I'd say a standard rebuild is not going to increase any hp beyond the stock 170. If the motor runs good, I'd say not worth the effort. You could do exhaust, the 'free TBI mods', and LT1 cam and get a bump - much anything much beyond that (like heads and intake) and your ECM is going to get confused and throw fuel at it to compensate, which will decrease the end result.

Although the TBI ECM is capable of learning, it's very limited i it's ability, and there is a fine line with TBI mods - once you cross the line you get into the need for custom tuning to get it to run.

I'm pretty sure though that you can swap in a 350 TBI motor from a truck or Caprice maybe, and get away with the chip from that vehicle and the knock sensor, and have a more powerful 350 TBI system - but you'll have to research this a tad more to verify what is involved for sure.

 

#1 - Exhaust. All of it is restrictive. Start at the heads with headers, then y-pipe, then cat, then cat-back. The '86-'90 TPI single cat application for aftermarket these parts is what you should be looking for.

#2 - Air cleaner. The single snorkel is restrictive.

#3 - Heads. The stock swirlport heads are fine for a stock 305 TBI, but as soon as you want more, you need different heads. The 305 TPI heads work fine.

#4 - Cam. The stock cam is pretty lame. See the TBI section for recommendations on a cam that will work well with the TBI. A new timing set should be considered a must when changing a cam. Stay with a factory-type roller lifter cam, and as long as the engine hasn't been seriously neglected with oil changes, the lifters should be fine to reuse. Inspect them when you change the cam.

#5 - Rebuild. If the rings and/or bearings are excessively worn, now you can consider finding a 350 block to rebuild and install. If you know the rings and/or bearings are worn, start looking for the 350 shortblock before doing #'s 3 & 4.

#6 - Computer tuning. You pretty much need it by now.

 

The best 305 heads are the 081 heads.