I had found what I believe to be the source of the metalic bits but hadn't traced the source of the brass particles. I think I found it. I couldn't remove the front cover until I removed the crank pulley because the bolts where a hair too long. Once off, I discovered the front engine cover/ timing gear cover has been brazed at some point. You can see a groove worn in the brass, deeper on the bottom edge. The timing gear is aluminum. It got me thinking, awhile back when I rebuilt the distributor, the back of the point plate had a deep groove worn in it to the point of removing the rivet heads and then some.
Are these 2 issues linked? What could be the source? Bent cam? Worn cam bearings? Is anything supposed to retain the cam aside from the front cover?
Front engine cover:
Points plate, rear view:
