Can I use the injectors from my 305 TPI injectors in a crate 350 engine using the 305 TPI induction system. Another alternative would be to use the injectors from a 85 corvette TPI system that I have on hand. What would be the pros and cons for each set up.

 

Using 305 injectors in the 350 you will run lean. Instead of having your injectors cleaned & flow tested you should invest in Southbayfuelinjectors Bosch 3 22#hr injectors.
You also need to have a 350 calibrator.

 

As he said above, but I think he meant computer not calibrator.

 

No I ment calibrator, Memcal .

 

Do I need to change the prom in the ECM from a 305 prom to a 350 prom, assuming they are not the same?

 

It either needs to be changed or you can have someone set you up with a piggy back memcal that will alter a few things that are different between the 305 TPI and 350TPI memcals. The ECM itself (7730 assuming its a 1991) is the same for 305 and 350 cars in that year. Its just the memcal thats different.

The TPI intake setup itself is the same between the 305 and 350..assuming its from the same year. GM did make different variations of the TPI system over the years.

 

Tell us exactly what you're doing here so we have a better understanding of whats being changed/swapped. Im guessing you have a 1991 Z28 with a 305TPI/5spd and you want to upgrade the engine to a 350 and swap all the TPI engine parts over to the new crate engine???
If so then you will need a knock sensor for the 350 engine, bigger injectors and a memcal swap or piggyback setup.

 

If your needing reprogramming feel free to send me a pm.
The 85 ecm is less than desirable most chose to upgrade from the 870 to the 1227165 86-89 maf ecm.
90-92 1227730 memcals can be reprogrammed if you don't care about knock sensor accuracy.

 

That is correct. My 305 blew. upgrading to a 350. I am using the correct 350 injectors with the 305 TPI induction system. If I retain the 305 prom what would be the downside. Would it run lean or just not have the full power that a 350 would give? In other words, would it harm the new engine?

 

It wouldn't necessary harm the engine but it wouldn't be running to its full potential. There are a dozen reputable members here who can help you out and get you a replacement memcal (chip) that will work perfect with your new engine. I can't see you spending more than $200 to have someone here get you what you need.
You've already spent a few dollars on the new engine and what ever else you needed to buy to get it installed. Don't skimp out on the memcal.

 

If you put the 350 injectors in and run the 305 tune you will be running a little rich.