This is the most powerful and durable distributor for small or big block Chevrolet engines that GM Performance Parts has serviced. For strength and high RPM stability the oversized shaft is guided by a sealed ball bearing and long sintered bushing, The treated coating on the shaft provides low friction. The advance assembly features chrome moly weights that slide on nylon pads for smooth, timing advancement through the entire RMP range. Also included are vacuum advance canister and billet aluminum housing that is CNC machined for greater accuracy. High quality cap with brass terminals.