Okay This might be asking a bit much but im trying to find out as much info as I can. I own a 1991 formula with the stock 305 t.b.i. my ideal goal is to have a a t.p.i. fuel injected 350 in that car. quetions are as follows...

1. what exactly is the diffrence between th 305 and 350 blocks?

2. is it possible to convert my 305 into a 350?

3. I also have a 1984 trans am that im parting down and it has a carburated 350. would it be easier to put a tuned port set up from a friends 86' on that block and swap everything out?

any information or suggestions would be a great help. thank you for your time.

 

1) bore size. That's the main difference in the blocks.

2) nope.

3) yes, that would work. Using a stock TPI setup off the '86, probably isn't ideal. WHy not stick with that carb on that 350?

 

Mostly because ive built a carb setup and proved that i could to some friends and a few gear-heads i know.. but but more than that i want something of a challenge to myself.
To prove that i can build a good T.P.I. setup to not only myself but the few that i run with. most all of them run an LS setup which yeah i know is nice but the tpi motors had some good bang for their buck and its something original yet diffrent from what you usually see.. around here at least.

 

First thing I would do is choose which ECM you plan to use to manage the TPI setup. There were a few oddball early TPI ECM's but most common are 87-89 MAF TPI with a 165 ECM and 90-92 Speed Density (MAP) TPI with the 730 ECM. The reason I think you should choose the ECM first is because that will determine what type of re-wiring you're gonna have to do. Its possible you can just re-pin the current harness to support a different ECM. Its also possible you'll need to swap in an entire different harness. Also make sure to get the correct PROM for whatever injector's you're gonna use (305 uses 19#, 350 uses 22#). Then as far as the TPI Intake itself, I would use the base intake manifold from the 86 (or a 87+ base manifold with modified center bolt holes), and then I would match up the rest of the TPI setup (top end parts) with whatever ECM you're using. So for example, if you decide you wanna run a 730 ECM for Speed Density TPI, use the 86 base manifold and 90-92 runners, plennum, throttlebody, etc). If you use the early MAF 165 ECM setup, keep in mind some years had a 9th cold start injector and some didnt. You should also consider that you might need to re-tune the PROM to match up with whatever might be in that Carb'd 350. The EFI setup dosnt care what type of cam is in there (flat tappet, roller, solid), but it can matter if the cam specs are way different from the stock TPI cam. Same goes for whatever heads are on there and how that compares to what came on TPI engines. Also, don't forget TPI is a high pressure fuel system, so if the car is Carb'd or TBI then you'll need to swap the fuel pump to a high pressure one. But yeah the swap you wanna do is possible!! Good luck!!