I am wondering if a TPI system off a 89 iroc-z 305 can be put onto a 89 350 TBI out of a suburban. I see the TPI has a crank position sensor and cam position sensor and the TBI i believe, doesnt use this. Also what all is different as far as injectors, throttle body, ecu or prom, ect. Any help is greatly apreciated.
thanks
chris

 

Yes, but you'll need 350 injectors. The 305 uses 19# injectors, the 350 uses 21# (I think, might be 22). Also, TPI does not have a crank/cam position sensor, which is why it fires all injectors at once, instead of only one for whichever cylinder is firing.

It does however have a knock sensor on the passenger side of the block. I'd be willing to bet the 350 block already has the boss drilled and tapped for it though. Also, you'll need the TPI computer, prom, and wiring harness.

 

Well when i looked on all data it gave part numbers for a cam sensor and crank sensor, but if i dont need it that would be great. The car already has the TPI wire harness from the 305 so that would work and about the prom, should i just get one from hypertech or does someone else make them custom? So there isnt any difference in throttle body size? Yes it does have a knock sensor in the side of the block as does the TBI systems. So the computer is different also? Could i just buy a reman computer for a 89 350 TPI?
chris

 

I did the research when I did my swap from a carb 350. The computer itself could be used, but you would need a TPI chip (either Hypertech or Jet for tuning perposes). You will not need to get new injectors. The 19lbs injectors will work fine. You will be running lean when you approach higher RPMs. You will need an adjustable fuel pressure regulator to take care of that. Set fuel pressure at 46lbs (stock is 42-43 lbs). I does need the knock sensor. The crank and cam sensors are not needed as Ward has said. As long as everything is in good working condition, you should be able to do the swap and get her going rather quickly. Any questions, feel free to ask.

Chris

 

I would try and get a stock PROM to start with, just to get up and running. That should give you a good base for tuning too. It is true that you can use 19# injectors at higher fuel pressure, but I would still keep an eye out for 350 injectors, especially if you plan to mod the engine. The TPI computer is identical between the 305/350, all of the differences in fuel/timing/etc are stored in the PROM. However, there are differences between TPI years.

-86-89 are mass airflow systems, requiring a mass airflow sensor
-90-92 systems are speed density, eliminating the MAF sensor
-86-87 will be wired for v-belts, with alternator on pass side, A/C on driver side (can be rewired fairly easily if needed)
-89 and up does not have the cold start injector, and does not have a hole for it in the driver side runners.

It sounds like you'll need an 86-89 ECM, with an 89 5.7 prom and harness, due to the missing cold start injector.

 

yes,everything from your 89 tpi 305 will bolt onto the 89 tbi 350.
You will need to swap all sensors from the 305 to the 350 or buy new ones whatever you choose.
I recently swapped a vette l98 into my 305 powered car and runs great on the 305 memcal.I used a 350 knock sensor and 350 inj. and retained the 305 memcal since I couldn't find one at the right price for a sd setup 350(those are EXPENSIVE!)
So yes,realistically if your 350 is just stock it will run fine with all the 305 stuff but,it isn't going to be a powerhouse by no means.
hope that helps