In my opinion go with Dave and Qldsubs suggestions. I had a friend help me rewire my 64 GMC 6000 we constructed our own harness with a 21 circuit harness from E-Z Wire sitting on the bench. The E-Z Wire harness was for my 56 and we decided that it was too much for the 64 as I did not plan on power windows, A/C and such for the 64.
I wish now we had just used the harness from the 56 by the time we finished the one we had constructed it had nickel and dimed me to death and we saved nothing. The E-Z Wire harnesses are by far the most inexpensive way to go, the quality is great and the price is right. They make a 12 circuit harness that is plenty for most and a 21 if you plan on adding power everything.
