MSD distributors should already be converted. They run off of a magnetic pick up system similar to the pertronix I believe.

Corvette Tach Drive, PN 8572
For Covettes or race cars using a mechanical tach, this is what you need. The billet aluminum housing features an unobtrusive tach drive which can easily be reversed for ease of installation. Plus, the drive is equipped with a grease fitting and backlash adjustment.
The Distributor is built around the PN 8361 Street Pro-Billet with the same components delivering accurate trigger signals and spark delivery. It also must be used with an MSD Ignition Control.

Street Pro-Billet, PN 8361
The Street Pro-Billet Distributor is the answer to your street performing needs. A vacuum advance provides economy and the adjustable mechanical advance gives you the ability to tune an advance curve for your engine.
Under the Du Pont® Rynite® cap and Racing Rotor is MSD's maintenance-free magnetic pickup. This is the same pickup that is used on 200+mph NASCAR stock cars! Each time one of the precision reluctor paddles pass by the pickup, it triggers the MSD Ignition Control.
For strength, the PN 8361 uses an oversized steel shaft that receives a QPQ coating for friction reduction and corrosion resistance. A sealed ball bearing and extra long sintered bushing provide high rpm stability and endurance.