1997 GMC 1500 4.3L swap to a 5.7L?

Question

Is it possible to change the vortec 4.3L to a carbureted 5.7L? Also would it cause computer problems on the truck to not have the vortec in there?

Answer 1

It can be done. You just need the motor mounts for the V8 block, the fan shroud for the V8, and upper and lower radiator hoses. The motor will bolt right up to the 4L60E tranny. Sell the computer and wiring harness because you wont need it anymore!

Problems. The tranny is electronically controlled. Your going to need to run the tranny as a stand-alone unit, and a controller can be found online very easily (do a search). If you don't get the controller, it WILL NOT work at all. It will go in to first gear and you can force shift to 2nd but that is it. Problem #2 is it isn't going to pass smog and is considered legal only for offroad use. #3, fuel delivery. You have to ditch the factory 60psi pump inside the tank for something that puts out a whole lot less.

It would be an easier swap to install the Vortec V8, because it is already a Vortec truck... I think you can just have the computer reflashed for the 350ci program, but I think there is another difference but not 100% sure. The fuel pump will work (both motors use the same pump). Your tranny will not need any attention. Plus it's FI so no farting around with a choke and the truck will run at extreme angles (upside down as long as it has oil pressure).

Answer 2

Why go carb when the fuel injection is already there.Program the ecu for v8 the harness is the same  

Answer 3

It is illegal to change FI to Carburetor for street use and yes the computor would not function properly so it will not work.

Answer 4

yes it will cause problems with the computer but the is kits out there to help you out.

Answer 5

Why degrade the fuel delivery system? The fuel injection works very well. The computer ties into everything and yes, altering it would cause problems.