GMC Truck Forum banner

My 5.3 swap into my 94 350 4x4 tech thread.....

4149 1
Ok, I've got my hands on a low mile 99 5.3 engine and solid plans are to drop this into my 94 k2500 4x4 that currently has a 350 tbi/4l60e with 183k plus miles on it.

I'm in the early stages of this swap so I want to get some of the simple details out of the way and some general rumors cleared up in terms of the tech side of this swap.

1) Motor mounts....5.3 to OBS....S&P makes these correct? If not who does? Anyone got a part number or price? I did not see anything on S&P's site regarding this...

2) I am considering using a Painless Wiring harness for this swap and from what I've heard and seem their harness has 4l60e trans control built into the harness. Is this correct and if so will my 94 4l60e work? I am unsure if the electronics are going to be different in current 4l60's vs. the older 4l60e's.

3) I would assume my stock radiator and trans cooler will be adequate for this 5.3....I will be upgrading my stock trans cooler with a secondary one soon so I'm not worried about that. It appears as this 5.3 has oil cooler lines so I will add a oil cooler as well. Anything I'm missing?

4) Do I actually need to find myself a 99 brain or will any 99-04 brain work with this 99 engine. I figure any one for 99+ should work since I'm not really using any stock wiring....any confirmation on this?

Any other tips or things I need to immediately concern myself with here?

1 - 2 of 2 Posts

47,426 Posts
Your 4L60E has a different TCC strat than the newer ones is all, I think it's lacking a 3/2 solenoid also. It may or may not work as the newer 4L60E's use this Ec3 stuff I believe it's called.

The '99 PCM will work better or you're going to have some strange lights come up with a newer one. Ask 99silver5.3 about this. BTW... '99 PCMs suck. I owned a '99 Z71 before my '01 and it was bad. '99s are also plagued by false knock from the PCM.

Your '99 has smaller injectors and a slighty different cam grind than the '00+ motors. So it will be down on power too.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.