Mark Hamilton is a genius. His wiring kits for 1965-1972 Chevrolets are the best. Full instructions and the finest quality wiring available. Fuse-able links, Bosch relays. soldering advice . . . complete wiring kits to supplement and replace your "faulty engineered GM wiring system." You are not replacing the entire harness - you are just adding and replacing and upgrading to your existing system. My '66 has great headlights now and I've had the kit for about 10 years with no problems ever. Call Mark at the number above - or go to his website and read about his upgrades. These kits work !