I have a 1986 K5 Blazer. It had a 305 Carb engine and lost compression in the #4 cyl. I now have a 1987 3/4ton chevy truck with a 350 TBI engine. We have already put the the 350 in the blazer and have the wiring harness from the truck out to where we can see it. Our issues are we need a wiring diagram for the both of them so we can see what we need to keep and what we can do without wire wise. We also have come to the conclusion that instead of pulling the wiring harness out of the dash of the blazer it would be better to wire the tbi by tapping in to the lines from the computer to the ones in the engine compartment. Do you guy agree? Another problem is that the Blazer has an 700r4 auto and the truck has a 4speed bulldog will it have to be flash for the auto? And any other issues you guys have run into or any help with the wiring would be a great help. And wiring schematics would be awesome. Thanks for you help.

 

The 700R4 is not electronically controlled so you are good there.

I would purchase the OE shop manual for both of the vehicles you are working with if you are intending on doing this swap by grafting the wiring harnesses together. When I do my carb to TBI swap in my 74 K5, I will be swapping over dash and everything from my 90 Suburban donor truck.

THIS PAGE chronicles the swap, but they use a pre-made harness.

 

This used to be a pretty common swap back in the day but I haven't known anyone to do it lately. I remember one swap where the computer was just stuck in a freezer bag and wire tied to the fender. Of course if you are going for the factory non-redneck look...

 

What about ill the one from the truck fit in the blazer? Any mods have to be done to it?

 

ill=fuel pump i dont know what happen during my typing

 

You will want to get a whole tank from a fuel injected vehicle to swap into your truck. The tanks are baffled differently.