MSD's Pro-Billet Small Diameter Distributor w/Red Cap and Steel Gear, fits 351C, 351M, 400, 429, 460 with iron gear. Must be used with an MSD 6, 7 or 8-series ignition.;CNC Machined Billet Aluminum Housing and Billet Aluminum Base; Steel Gear Installed; Polished steel shaft is QPQ coated and guided by a sealed ball bearing; Advance plate and weights are fine blanked from chrome moly steel and QPQ coated for friction reduction; Advance weight pins are staked and tig welded to the plate; Easy-to-adjust mechanical advance with supplied springs and stop bushings; Nylon pads ensure smooth operation of the advance weights; Mechanical advance assembly can be locked out for crank reluctor systems; Maintenance-free magnetic pickup and precision reluctor create stable reluctor signals throughout the rpm range;