I don't know if all the cam companies are useing them but i've got a Bullit 4/7 swap (big bump) sm/blk cam that has a cast iron distributor gear and rear bearing pinned and bolted to the billet roller. i was told i coud use a steel gear or a Bronze distributor gear on it. I'm asumming they are doing this to save the cam in case someone doesn't use Bronze gear on their race engine.
Zip.