I found a 350 tpi for sale for 600. The guy says it was rebuilt 40k ago and still runs well. Assuming that it is good to go.. Can I just drop this into my 88 iroc which has a 305 tpi in it, and use my same ECM and harness or do I have to have the harness and ECM from the 350? I was thinking the motors should be identical other than the bore. Oh, as a side note, the 305 TPI that is in my car at the moment is from a 85 or 86. It has the side bolt valve covers.

 

In answer, the 305 TPI wiring hardness is the same as is the ECM (except you will need a 350 prom...Fastchip has a good one) . Outsid of adding any new replacement parts you should be good for this swap. Your last statement about the 85/86 305 TPI in the car, was that a complete swap of everthing from that year????

 

That I don't know. I bought the car from someone who didn't even know it wasn't the original engine. I just know its not the 88 305. if so it would have center bolt valve covers, this one has side bolt, and the accessories are on the wrong side for an 88. Being that its a tuned port its gotta be from an 85 or 86, and I know the tuned port setup was on the motor at time of transplant because they dented the runners with the engine pull chains. I am considering the swap because I can't make the thing run right. I was gonna just change injectors and hope for the best, but now I am hearing valvetrain knocks. There is something seriously wrong with this motor. So its either top half of motor, or a different motor.

One other thing I am considering is converting this motor from tuned port back to carb. I am thinking I will need cam, lifters, push rods, new heads, intake manifold, carb, hei distributor, and then can I just use a fuel pressure regulator and keep in tank pump? What else am I not thinking of for this?

 

Update.. Looks like I'm out of luck on the 350 tpi. The guy sold it already.

 

Hi all,

I'm going to be swapping a 350 into my 89 iroc z (tpi) in the future and this answered one question (that I can use the same harness and ECM just need a new prom).

Other question is though what else will I need to change besides the engine? Will I need to change the injectors?

I know there are stickies and I've read through them but some places recommend changing injectors, others say the stock 305 ones are fine?

Thanks,
Bez

 

if you are going with a totally stock 350, you will need 22 lb/hr injectors. they will handle exhaust and a cam upgrade as well before they reach their limit.

 

You also will need a knock sensor for the 350.

 

this answer my question asweel on the wiring and ecu, but im not sure what a prom is,

 

The Prom (aka CHIP) is needed to re place the 305 one in the ECM to run the 350 with the new 22# FI & other changes needed. Again look at Fastchip.com.