MSD 8584 Billet Distributor CNC machined billet aluminum housing and Dupont Rynite base Easy-to-adjust mechanical advance with supplied springs and stop bushings Maintenance-free magnetic pickup and precision reluctor create stable trigger signals throughout the RPM range Polished steel shaft is QPQ coated and guided by a sealed ball bearing Advance plate and weights are fine blanked from chromoly steel and QPQ coated for friction reduction