MSD cam sync plugs are designed to install in place of a traditional distributor when running an aftermarket sequential EFI system with coil-per-cylinder ignition. The cam sync plug provides a hall-effect cam sync signal that the EFI system needs in order to reference the 1 cylinder. These plugs contain a steel distributor gear and they drive the oil pump in wet sump applications. Cam sync plugs are plug-and-play with Holley EFI and compatible with most aftermarket EFI systems.