I have a 91 Firebird TPI 305... Motor is still running good, but has quite a few miles on it... I want to do some appearance / performance upgrades to the TPI setup / runners / etc... Can I use the same setup later when I decide to get a new motor, possiblly a 350? (I know new injectors will be required, etc...)
Thanks,
Rafael

yep. The TPI's are the same.
The injectors and knock sensor are different. You should change the programming in the ECM as well though it will run on 305 programming.

The ESTC (electronic spark timing control) module is different too, to go along with the knock sensor, but otherwise, excluding the parts previously mentioned, it's all the same.

Are you sure about that? I've never heard or read this before ...

I knew the knock sensor is different such that it will detech the harmonics of the large bore 350 compared to the 305. The sensor itself still outputs the same signal, hence I would not think the eletronic controls need to be any different. Perhaps the timing advance would be different, but that is in the PROM.

I am curious to hear more about why the ESC would be different.

Mark.

I'm not so sure that the module is different. I replaced my sensor when I swapped engines and all's well.

When I did the swap on my Blazer from the 305 to the 350 I researched every sensor to make sure that the engine would run perfectly as soon as I fired it up. I found that the ESTC modules have different part numbers for 305 and 350 engines. I never even tried to run it with the 305 ESTC, but it runs great with the 350 ESTC. They may not be any different, but if they aren't why do they carry a different PN? It wasn't a chance I was willing to take, without having a very knowledgeable person tell me that they were the same, and I couldn't find anyonw who would do that at the time.