"Engine Swap"... Vortec 4.3L V6 to Vortec 5.7L V8

severedchris said:

I am almost finished with my swap and these are my findings so far:

1. You will need a set of V8 motor mounts...save your ones from the V6 they are worth some$$$$$
You can re-use your old nuts and bolts, the holes for the V8 mounts are already pre drilled from factory in the frame just further foward.

2. You will need a radiator from a V8 truck...they are larger and include the engine and tranny oil coolers
You will need rubber insulators and brackets from a V8 truck in order to mount the larger V8 radiator in the V6 model pickup or SUV
If you can get the Transmission cooler lines from the V8 truck I would get those as well the V6 lines will work but are bent for the smaller radiator
the proper ones would make for a cleaner install.

3. All of your front running gear I.E. Alternator, A/C Compressor and Brackets will work on the V8.

4. You will need the throttle cable and Cruise Control Module and Cable from the V8 model
The V6 cables will work but will not clamp back onto the factory brackets b/c they are shorter, the cables from the V8 make for a cleaner install.

5. The starter for both the V6 and V8 models are the same.

6. You will need the Engine Bay Wiring harness and the ECU from a V8 truck that is the same year model as your V6 truck.
Others will work but Once again the correct harness will make things simple...If anyone has any wiring diagrams for the Vortec models please post them.

7. You will need the fuel lines from the V8 truck the V6 lines are too short...it is best to replace the two O-Rings at the junction on the back of
the motor if you undo the lines there.

8. You will need the Gauge Cluster from a V8 truck otherwise your RPM reading will not be correct as the V6 Gauge Cluster is Calibrated differently.
Your V6 cluster will work but your RPM reading will be slighltly incorrect.

This is all of the info that I have hunted down and gathered while doing my swap......If you have done this and have additional information or
you have any knowledge on differences between models/submodels please add your info here so that this will be readily available for people
doing this swap in the future as well as pics from your Vortec V6 to V8 Swaps!!!...I will be posting pics asap.





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