4.3L to 5.7L Engine Swap...HELP!!!

[jacord]

Hi, I was wondering how difficult it would be to swap a 4.3L for something with a little more guts. I have a 1992 K1500 and I need to know what componets from the 4.3L I could use. Obviously I would need a new intake manifold, headers, ECM, and a couple other things, but could I use the same Throttle Body and wiring with an ECM from a 5.7L that is also a 1992. What sensors and stuff would I need to change? I wanted to get a crate engine and not go and pull one from a donor that already needs to be rebuilt. This would be my first engine swap and I was really hoping it would go smooth and give the extra power my truck is craving.

[Z71Jason]

Sell your 4.3 truck and buy a 5.7 truck. There are plenty out there.

[broughy84]

should be fairly straight forward, the starter is the same i believe, you can use the same TBI unit, but you will need the 350 injectors. You will need a PROM for the ECM, you don't need to change it all. Manifolds, both intake and exhaust, a shorter fan shroud, and possibly a larger radiator, I don't know what size the 4.3's come with, but my 88 350 has a 4 core.

[wafrederick]

THe 4.3 computer will work with the 350.It will composate for the 350.You have to move the motor mounts forward.The wiring will plug in with no problems.

[plzzblow]

i have an 1989 s10 4x4 4.3l. at one time i had a 350ho deluxe chevrolet performance crate motor. it was four barrel carb. i switched back to a stock 4.3l tbi and had to put the wires back. now im wanting to swap in a 5.7l v8 tbi from an 89. you can get the motor mount adapters from summit for about $60. i beleive. they are made by advanced adapters. i would use the stock 4.3l radiator. i bought the be cool aluminum radiator for v8 in s10 and it was thinner than the stock one. it also did no better to cool the motor and im told that a copper or brass or whatever the stock one is...is more durable for long term usage.

[93LT]

I just bought a 1995 K1500 that was factory 4.3L and the previous owner put a 6" lift kit, and a 3" body lift on it with 36" Mickeys. Blew the 4.3L and swapped in a 5.7L.

As has been mentioned, no need for a ECM swap, just the eprom. There are 'some' wiring harness differences, but not enough to keep you from getting it going. You'll need to trim your fan shroud or replace it.

[junk yard doggie]

Last one I did was 10 years ago. Used the V6 radiator, it's still in the truck to this day never had a problem. Used the same motor mounts, Had to move them of course. Had to move the trans cross member as well. The V8 sat further forward I believe. I had to shorten the drive shaft since I used an odd ball transmission. You may or may not have to do that on yours. I used a carb motor so had no electronic computer issues. Yes I did trim my fan shroud down and re used it, worked just fine.

I had no choice on changing my engine since the V6 was bad. If yours still runs good, I would think good and hard before starting a project like this. It might become one of those forever projects, getting things changed over and working bugs out. This is not one of those weekend 30 pack of beer with your buddy's type of jobs. Any one that says different is full of shit. Also the little things that you don't think of will nickel and dime you to death. I don't want to sound negative here, just want to state the cold hard facts.