I have a 91 rs with 305 tbi.I have a 350 tpi, and get my hands a tpi off a 305 tpi off a GTA along with the computer .What is the difference in the 2 if any?my 350 tpi is a 88 also.

 

if you can find a '90-'92 TPI the swap will go a lot easier, see the thread at the top on repinning the '90-'92 TBI harness to TPI (using the 1227730 ECM)

AFAIK the only difference between 305 tpi and 350 tpi is the injectors and the PROM, besides the usual differences between model years (different ECM's, MAF vs speed density, cold start injector, etc)

since your 350 TPI is an '88 if the other TPI from the 305 is a 90-92 that one will swap easier, don't have to worry about wiring all the MAF stuff

 

wow that was a really unorganized question. let me see if i can help since i am doing the same thing.
first the difference between an 88 and a 90-92 is the type of tpi. prior to 90 they were maf [mass air flow] and after that they were map [manifold air pressure].
the maf measured air flow with a hot wire by the throttle body and sent the info back to the computer.
the map measured manifold air pressure, no hot wire.
they are not the same thing.
now i am using a 91 350 tpi on my 305 - previously tbi. you will need to pull every wire - cut nothing - you can sell it - and pull the computer box and all the wires going to it.DONT CUT ANYTHING.
before you install the new tpi have someone go through every inch of it to make sure evrything flows - ie there is no broken or weak wires. the conmputer needs nice clean signals. have them check it hooked up to the tpi, so you know where everything goes.
dont forget to pull the distributor too - make sure it is melonized [look it up].
that is it in a nut shell.
now go to the tec part of the board - hit HOME and then look at the tec articles - which will give you a blow by blow on how to do it.
take the fuel pump out of the tpi unit and install it into the 305 camaro - and the fuel pump too.
the chip will not work - it is set for a 350 you have a 305. also your injectors are different too.
that is a start. and READ READ READ everything on the conversion process.
good luck.
and dont forget to use the button in the red line at the top of the page.

 

I just want to tell you thanks for the info.