Once we tore into it, it proved less difficult than expected. We cleaned up a lot of electrical spaghetti by tearing much of the old wiring out of the car: gone were the ignition system, the gauges (ousted in favor of Holley’s PN 553-103 -inch touchscreen), the alternator exciter wire, the old stand-alone trans controller, and the switches for the fuel pump and fans. It was all replaced by the various Holley harnesses: PN 558-200 for the injectors, PN 558-308 for the balance of the engine, PN 558-405 for the trans control, and PN 558-406 and PN 554-100 for the accessories. Those harnesses are pretty well labeled with what goes where. Only the optional accessory controls really require a hard look at the instructions.