Official NBS 4.3v6 to GEN 3 V8 swap Guide

[zebra]

finding a harness from a manual truck will be the easiest way, but you can use either. since you'll have the manual t-case, you don't have to worry about finding one with the electronic 4x4 wiring. also, if you use a harness from an auto, you can pull out the transmission wiring (with the exception of the VSS & reverse). click my sig to find the company i sent mine to (because i didn't feel like fiddling with it). it also shows the jumper you'll have to add to the fuse block for the clutch safety switch (which you can just reuse from your V6 harness).

[3car]

finding a harness from a manual truck will be the easiest way, but you can use either. since you'll have the manual t-case, you don't have to worry about finding one with the electronic 4x4 wiring. also, if you use a harness from an auto, you can pull out the transmission wiring (with the exception of the VSS & reverse). click my sig to find the company i sent mine to (because i didn't feel like fiddling with it). it also shows the jumper you'll have to add to the fuse block for the clutch safety switch (which you can just reuse from your V6 harness).

Thanks for the info. I read over your thread, and Current wiring is about 25 miles from me. Convenient. lolc

[Frenchy]

No. Mine is an auto harness. It already has all the manual stuff in it, just shut off. Plug it in, program the PCM with a manual trans file. Drive truck.

[zebra]

funny... my harness came from an 01 Tahoe & wouldn't start until i figured out the thing with the clutch safety jumper. no power to the starter - just like trying to start without pushing the clutch pedal in.

[3car]

I already have an issue with the clutch safety switch(I think), sometimes it just wont crank. Turn the key again and its fine.

[blacstar]

bypass and see what happens

[3car]

If this info has been posted before I apologize, but I can't seem to find it. My truck is an 02', so I know I at least need a 99-02' harness, sensors and computer. But, how much newer can the actual engine be? In some places the 07-08' engines with low miles are cheaper than the high mileage older ones.

[Frenchy]

Right up to 2013 with a bit of work.

[3car]

I've got a motor and accessories, but finding a flywheel has been a bit of a challenge.

[Wrkd_LSX]

you need to get a 2004-up harness. the pinouts are different. if ur truck were to come with a V8, it would have been dbw.

so is it possible to move the pins to make the 99-02 dbc harness to fit a 03 4.3 dbc fuse block?