I have an AMC 360 that has been rebuilt (started for the first time this weekend) and have already wore down the distributor gear (sharp). The reason for the rebuild was that the engine was using oil and that I "apple cored" the gear on the camshaft for the distributor. When I rebuilt I put all new parts in: (I am not sure what matters so I will list everything)

block bored (.30 over) & vated
piston & rings
oil pump
power steering pump
water pump
RV cam
Crank shaft
heads redone (valve job)

I also did the oil modification for the rear bearings. I have the chevy 350 TBI set up and an edelbrock intake. So as you can see I have some money tied up in this engine. I have ran it for about 4 hours and the distributor gear is gone, the gear on the camshaft looks good still. I have been told I may need to go to a brass/bronze distributor gear.

1) What could be causing this?
2) What holds the cam in place on a 360?

Any help would be greatly appreciated since I am really frustrated with this problem.