does anyone make a wiring harness for such a swap??

 

come on someone has to make something

 

http://northwestoffroad.com/parts/wiring.html

 

Never buy anything from NWOR... EVER.
They still owe me >$400 for a screwup that THEY made in 1995

The two most popular companies for wiring harnesses are Howell and Painless. I've used Howell for a 4.3 TBI swap as well as their speed sensor delete chip with good success. There is another company which re-works factory harnesses, but I can't remember their name.