One of my friends restored a 67 Mustang and put one of those aftermarket wiring kits that cost $900 from NPD...and it didn't work. He spend several months and finally took the car to a custom electrical auto guru, and he couldn't make it work either. Just straight stock Shelby dash gauge and a Pertonix ignition. He tore it all out and bought an Alloy Metal reproduction harness from Branda and all was good.