An adjustable mechanical advance assembly allows you to get the most performance out of your Vette's engine by custom tailoring a timing curve to fit your application. Corvette owners can now replace their worn out Magna-Pulse distributors with this precision Pro-Billet Tach Drive Distributor. Advantages such as an accurate magnetic pick-up, oversized shaft, vacuum advance and a billet aluminum housing are just a few of the MSD advantages. Inside the billet housing, a sealed ball bearing and long sintered bushing guide a 0.500" steel shaft for high rpm accuracy. A special reluctor is mounted to this shaft and is responsible for triggering the magnetic pick-up. The tach drive assembly is compact to clear the firewall and linkage. It can be repositioned easily to fit different applications plus has a grease fitting for lubrication.