2000 Silverado LQ4 & 4L80 Swap Question

[1badblazer]

I have an 2000 Silverado 4.3 truck and will be swapping to a LQ4 and 4L80. I am getting an whole 04 Silverado 2500 2wd that is wrecked. What I am wondering is since I am going to go ahead with the LQ4 and the 4L80 at once what am I going to have to do to make the trans work? Can I use the harness and computer from the 04 or do I have to use a 1/2 ton v8 engine harness and redo some wiring and get my computer flashed just like if I was just changing the engine itself? Sorry if this is a dumb question but I have been doing some reading and haven't found the answer I was looking for. Thanks in advance

[PitchBlackC3]

The easiest swap would be using a 99-02 V8 harness and PCM. You would need a DBC throttle body to go with it though.
Your 04 harness and PCM can be made to work, but there will be issues integrating with your 2000 model BCM, HVAC and harness plugs.

[1badblazer]

So could I get a 99-02 harness and DBC Throttle Body and use my PCM that is in the 2000 Silverado and just have it tuned?

[kerrige]

No your 2000 throttle body is for a 4.3 that won't work.

[PitchBlackC3]

No your 2000 throttle body is for a 4.3 that won't work.

Actually as long as it is a compatible hardware number, it can be programmed for a V8.

[kerrige]

Actually as long as it is a compatible hardware number, it can be programmed for a V8.

If this is true then all of the 96 and up vortec DBC tb's will work with the 2000 6.0? The 4.3 tb is the same as the 5.0 and 5.7 if I remember correctly. I am really not sure so don't quote me haha but i am pretty sure it wont work.

[1badblazer]

No your 2000 throttle body is for a 4.3 that won't work.

I was asking about the computer being comparable not the throttle body because I know it won't work.

So if I get the DBC throttle body and the harness from the same year, what do I have todo as far as the transmission is concerned to get it working correctly?

[PitchBlackC3]

If this is true then all of the 96 and up vortec DBC tb's will work with the 2000 6.0? The 4.3 tb is the same as the 5.0 and 5.7 if I remember correctly. I am really not sure so don't quote me haha but i am pretty sure it wont work.

My bad, I had PCM on the brain when I read that..... I was thinking 2000 4.3L PCM.