Swapping a 4.3 with a 5.3 Guide

[MajesticZ]

Hey guys, sorry if this is in the wrong place as I’m new. However, I have a 2008 Sierra with the 4.3 automatic 3.23 diff. I have a few 5.3’s from salvage, but I need to know exactly what I need to do the swap. I know I need a PCM but has anyone done this before or have a guide of doing it and the parts needed? I also need to know what year 5.3’s will work with my truck, I want everything working electronically. Thank you

[CamGTP]

Must be a GEN 4 engine from 2007.5+ to work and make it easier.

 

2007.5-2009 are AFM only and non VVT.

 

2010-2013 are AFM and VVT.

 

I'd probably do a non VVT engine. You'll need the harness and fuse block. A 2007.5-2009 computer would already have a 4L60e transmission. The computer will probably want to be flashed again while hooked up to the vehicle after the swap so the PCM and TCM both have matching operating systems.

 

If you had a GM MDI tool with a subscription service to the TIS website you could flash the vehicle with the VIN number of a truck that had a 5.3/4L60e. Could even just take the VIN from the computer you end up using, flash the newest OEM file for that VIN into it. Then it should all work with the engine/transmission and the security system should be fine.