I just threw my Pro billet MSD in with a E-303 over 2 years ago and never had a problem. I pulled it last month and the gear looks great. I assume you are in the same boat and would tell you tp go ahead and stick er' in. The gear on the B cam is the same as the stock cam, thats why you can throw a cam in without changing the distributor. I dont see why it cant be done the other way around, ya know. Just my $.02