ACCEL Electronic Advance Distributors let you retrofit early distributor-equipped Big Twins and Sportsters and give you the option of running in either single- or dual-fire mode. They come with 14 preprogrammed advance curves that can handle anything from bone-stock engines to high-compression ground-pounders and feature on-board rev-limiting and an LED for easy static timing. These electronic advance distributors work with or without vacuum-operated electrical switch input, have a machined aluminum housing that doubles as a heat sink, and can be installed without removing stock heads and barrels.