This Napa Echlin KS6643 switch assembly is the perfect replacement for your 1977 Ford F500 P500 Ranchero's ignition starter switch. The switch is designed for vintage parts and is dustproof and durable. It is compatible with a few interchange part numbers such as 53-27611 and IGNB10369. The switch's manufacturer part number is KS6643 and it is a gray color. It is made in Taiwan and is not a universal fitment or a performance part. This switch is a great addition to your car's interior parts and accessories and is a must-have for anyone looking to replace their vintage car's ignition starter switch.