I have a 90 chevy C2500 Scottsdale with 350TBI engine, SM465 4 speed trany. I want information on swapping the 350tbi to 454tbi. I know have to swap prom chips or ecm and upgrade cooling system. I also know if the 350tbi wiring harness might work depending on if it plugs into the ecm. The 454 will out of a 91-94 c/k series truck.

 

Hey,
Im doing a project very similar to yours. Mines an 89 1500 4x4. Going from a 350TBI to a 454 tbi as well. I know i need a 454 Ecm. I know also that i have to beef up my cooling.

Some guys i talk to say i need the 454 wire harness, some guys think it'll work. And others say the 350 will work...yea

But ECM and cooling upgrade is a must.

Everything tranny wise and motor mounts should bolt up. But it'll be tight under the hood when it comes time to do some wrenchin.

Not sure about the front though..Like will the power steering box bracket will bolt up from the 350 to 454....stuff like that.

My question though is, Does it matter what tranny you put behind it? Will it matter to the ECM???

Thanks guys,
and hope this helps.