Can't you buy every harness you need? I know they make them for 68-70 b-bodys. I pretty much did this car. It came w/ all new harnesses (uninstalled) they only one that was in the car was the one from the fire wall back to the rear. Eveything wlse I hung myself. The bigest PITA was the steering column harness. The dash harness led me to get reading glasses and I had to adjust the engine harness to BB from SB, but other than that it just took time. Of course it helped that I had no interior or heat/ac box to mess with.