i am wapping an 89 305 tpi for a 91 305 tpi...will i need to change the computer and wiring harness..also is there any other things taht may be different?

 

im pretty sure in 1989 they used a maf sensor and in 1991 they went to map sensor ...so yes you would need a different computer ..

 

could i just run maf on the 91 with the 89 computer?

 

Just put the 89 TPI top end ont he 91 motor.

The motor itself is the same (or at least, plenty close enough); just put the right stuff on it to work with the electronics and wiring that are in the car.

 

ok this is what ill do...what parts need to be swapped over...the intake manifolds should be the same right?

 

Nope. The intakes are different. You need to just use the block and heads from the 91 and then bolt all of the 89 parts back to it.

 

the 91 is going from an auto to a manual..is there any differece or it will it bolt directly on

 

I think you were saying the same thing, just to a different level of detail.

No difference as far as the engine is concerned. You will need to install a pilot bearing in the crank.

 

are u sure the intakes are different...by the egr the casting # is the same.

 

I can't say which part is different. I think MAF engines use a 7th fuel injector for cold start, but maybe GM dropped that for the 89 MAF engine. The fittings and sensors going into the intake will also be different, maybe? I just think it's better to use the entire 89 setup so that no little mistakes get made, like forgetting a sensor but not knowing where it goes because your new intake has a plug in it instead of a sensor.

 

Oooopps!!!! Been looking at a 2.8 too long Kris?

This is a V8. That'd be a 9th injector.

But that goes into the runners, not the base. AFAIK the 91 base is the same as 89, but I could be wrong.

So yeah, keep your old plenum, TB, runners, wiring, sensors, and so forth; just use the other long block and out that stuff from your car onto it. Anything from the 91 that's the same as the 89, use it; anything on the 89 that's different from what's on the 91, use the 89 stuff. Pretty straightforward.

 

That's it! hahahahaha

I really need to get out of the 2.8 business! None of my Buicks have a cold start injector!

Thanks for the save!