Distributor gear applications are:
hydraulic roller cam - steel
solid roller - bronze or polymer
flat tappet(hydraulic or solid) - cast iron
First of all check the bottom of the distributor gear and see if you have any wear. There is a deck surface with a guide hole in it inside the block. You can see it using a flashlight with the distributor removed. I have seen a few distributors with the gear installed to low on the distridutor shaft. This results in binding the distributor gear against this deck surface when you tighten down the distributor hold down. End result is chewed up distributor gear and in worst case the cam gear will be worn. If you put in a new distributor gear with a worn cam gear it will just cause spark scatter and also the gear will wear out faster the next time. Make sure you change the
oil also. Good luck.
Jeff