MSD's V-Series ignition will get your Harley fired up. It allows you to select your own timing curve for a smoother idle and snappy throttle response. You can also choose between Dual Fire or Single Fire, kick start or electric start and select the VOES curve that matches your riding style. A programmable rev-limiter keeps things under control should you miss a shift or break the driveline. Must be used with a 3 Ohm Single Fire coil when used in Single Fire mode. Fits completely behind the stock engine ignition cover on 1971 thru 1997 Sportster, 1971 thru 1983 Shovelhead and 1984 thru 1999 single cam Big Twin. Does not fit Fuel Injected models.