Utilizing thedurable and dependable High Energy ignition (HEI) system pioneered by GM, these distributors avoid the unsightlywiring of stock Ford electronic ignition systems by installing this one-piece distributor with an internally positioned coil and module. Easy to install: just connect one 12-volt hot wire to the distributor (has optional tach hook-up). These units offer calibrated advance curves that are optimized for maximum combustion efficiency and for the elimination of detonation damage and throttle ping. Assembled from precision-made parts for advance curve smoothness. Offers longer term durability and a higher voltage spark that permits a bigger spark plug gap, resulting in more power and reduced plug fouling. (Technical Note: Gear not compatible with roller cams. If using roller cams, please contact the cam manufacturer for proper gear selection.)