Holley EFI distributors are designed to plug and play with Holley EFI systems. The design includes dual Hall Effect sensors for the crankshaft and camshaft signals. They can be used as just a crank speed input as well as providing a cam sync signal, for sequential fueling operation. They can also be used for crank and cam signals for Coil-On-Plug applications. The precision machined shutter wheel design ensures accurate timing, even at very high engine speeds. They can be used with other EFI systems that support Hall Effect crank and cam sensors.