Conversions & Hybrids - 2001 v6 to v8 wiring Question

Can I just get a V8 engine harness on passenger side and plug into the v6 harness where the two connectors connect at passenger kick panel or will I need to change the whole harness that runs behind the dash and out the drivers side?

You won't have to change it, just get a pin diagram and match the wires.. There are differences.

What about pcm. Will I have to have one from a 2001 model or can that be changed with hp tuners?

You will need a V8 PCM & wiring..

I meant will I have to get a 2001 V8 pcm since the car is a 2001? My fault..

99-02 will work...2002 is better, more tuneable.