In the MSD catalogue:

There are notes,posted in their item descriptions about the necessary gear for a roller cam. There is a special number for the steel gear on their billet distributor.

I also understand there is a new composite gear for this same application, but you need to carry a spare, anyway.

Gary
ps: I think it took Jamo about 20 minutes to change one of these gears on the side of the road with the ASSistance of some Gasholes. probably coulda done it in 10, alone

John

Actually ,the distributor gears are bronze and are designed to be sacrificial . I myself had the same thing happen and replaced the gear. I have been through three of them in 15,000 miles and that is considered normal. It is not a big deal really, as long as you warm up the engine they will go at least 8000 miles. If you have a roller cam, you might want to put the bronze gear back in.. here is an article excerpt from Car Craft:

Softer bronze gears are typically used when running a billet steel roller cam, because the roller cam cores aren’t as hard as those on flat tappet cams. Bronze gears have a bad rap for wearing very quickly, but that’s in part due to inferior yellow-brass gears sold by some companies. Quality nickel/bronze alloy gears like MSD’s are made from a tough alloy, so they should live for years provided you don’t beat on the motor before the oil’s hot. Sometimes your first bronze gear may wear out quickly as it massages the cam gear. John mentioned that if the cam gear is poorly made, the first bronze gear may destroy itself deburring and reshaping the cam gear, but the second bronze gear should wear in faster, work more smoothly, and live longer. Bronze gears wear more predictably since they’re the same hardness all the way through, whereas iron gears are only hardened on their outer layer (0.0005- to 0.0015-inch deep). Remember to check ignition timing; as the distributor gear wears, the timing will retard.

The key here is to warm up the engine before you use much throttle. When I started to do that ,the problem went away. Check with Elliot Franklin at Mustang Corral in San Jose - he knows these engines and the bronze thing....

See you at breakfast soon

Steve

MSD never "switched" I just bought another of these things...