TPI-RS

iTrader: (6)

Hey guys.

Alright, first just a little bit of history on the car...

I purchased my 1991 RS about 4 years ago. It was a 3.1L that didn't run. I picked up a TPI 305 and did a motor swap in the car. I recently found a real clean 350 that has somewhere less than 15,000 miles on it. Now... I have about 100 questions +/- on what needs to be done if I go ahead and purchase this 350.

1: The 350 motor is a TBI... I want to keep the TPI set up...
a. Can I use the 305 Intake manifold?
b. Can I use the 305 TPI Intake and runners?
c. What other parts are necessary for a TBI to TPI conversion?
1. are the sensors the same
2. is the cam / lifters / etc the same in a TBI engine opposed to a TPI engine?

2. I have a wiring harness from a 1991 Z28 305 TPI car...
a. Will the wiring harness be identical from a 305 - 350?

3. I know I need new 350 Injectors... Is there anything else that isn't a direct swap from 305 - 350?

4. My computer is new from GM. It is a 305 TPI computer with a 305 TPI prom. I assume I need a new 350 computer and a 350 prom? Is this correct?

Okay, so it isn't 100 questions. But I'm sure it isn't only 4 either.

I'm sure someone has done this. I looked up a few posts using the search feature but failed to find anything quite like this. If there is one out there, feel free to point me to it please.

Please, any advice that anyone has would be great. I'm trying to see if it is worth it to do this conversion. Money is tight right now so if it is going to cost me an arm and a leg it isn't worth it, however, this is a pretty good deal on the 350 to pass up without at least looking into it.

five7kid

iTrader: (14)

Yes
Yes
Except for the knock sensor.
No, but that doesn't mean the TBI cam won't work with TPI.

Yes.

Aforementioned knock sensor.

Either that, or reburn the PROM.

TPI-RS

iTrader: (6)

Thanks for your response. You said that the cam is different however you don't think this will be an issue? I'm no mechanic I just enjoy working on cars for fun so I learn as I go. From what I have heard, TPI motors are 'touchy' when it comes to modifying them, so I want to make sure there will be no issues. Also, you said I can reburn the prom. If I do that, will I need a 350 Computer, or is the computer the same for a 305 and 350.

Thanks again for your response!

five7kid

iTrader: (14)

The '90-'92 "speed density" systems are finicky about changes, but respond well to PROM tuning.

The '86-'89 "mass air flow" systems are forgiving to changes but somewhat limited to the higher horsepower engine modifications.

Since you have a '91 harness, you need '90-'92 hardware and computer.

TPI-RS

iTrader: (6)

Good to know... Thank you!

Hopefully I'll be doing this soon if funds allow, I'll keep the post updated with progress if / when it happens!