24v to 12v swap?

[pro99]

I looked and looked but can't find the thread about swapping out a 24 for a 12 valve motors. I have a 99 24 valve auto 4x4 and want to replace it with a 12 valve 6sp 4x4 manual trans. I need to know do I need a new wiring harness and pcm or can I use whats in the truck and do little or a lot of rewiring? I only need to know about the electrical not mechanical part of the swap. I know its been done from 24 to 12 valves but I also want everything to work like tac, a/c, cruise and all.



Thanks Charles