MSD 85805 billet distributors are one of the finest street performance and racing distributors available. The Ford 351W MSD distributor housings are precision-machined on CNC lathes from billet 6061-T6 aluminum to within +/- 1/1,000 in., producing a housing that's stable, lightweight, and less prone to flex. They feature an upper-sealed ball bearing to guide the distributor shaft and prevent shaft wobble at high rpms, and O-rings at the bottom of the base for improved oil control. The shaft is polished and QPQ-coated to minimize friction and allow the distributors to operate through 10,000 rpm. An adjustable mechanical advance assembly allows you to accurately and easily modify the advance curve to match your specific application. MSD premium distributors come complete with a race rotor and alkyd cap.