This afternoon, I did everything but pull the camshaft and disassemble the head.

I think much of the damage I saw was a result of the engine running with an inoperable oil pump.

Here's the list:
Two broken top piston ring in #2 and #3.
Slight damage to the piston bore of #2 and #3 cylinder
Heat damage to #1 pushrod bearing.
Physical damage to the #2 pushrod bearing
Little brass-alloy bits in the sump
Two small steel bits in the sump

and of course..Sheared distributor shaft gear.

The little brass bits in the oil pan are indeed a coppery-brass metal of some sort. They came from the #2 pushrod bearing surface of the crankshaft. Seems that this crankshaft was balanced when it was rebuilt 300,000 miles ago. It looks as if the machine shop took some metal off of the #2 surface and there was a thin sheet of a copper/brass alloy between the pushrod and the crank. That metal deformed and shredded under the low/no oil condition. The #1 pushrod bearing was "shaved" and is missing a thing strip on the edge of each bearing surface. Very weird but all quite consistent with running w/o oil.

I disassembled the oil pump and found no damage internally or externally. It turns freely and shows no signs that there was anything wrong with the inner gears. The brass distributor shaft bushing in the block is also smooth and intact. Question is... where did that distributor shaft pin get off too?

Soooo.... for no obvious reason, my distributor shaft gear came loose from the shaft ceasing to run the oil pump but continuing to keep the cam, crank, and distributor in synch. The heat burns on the shaft indicate that the gear was turning while the shaft was not. Loss of oil circulation led to lack of lubrication on the pushrod bearings leading to heat and physical damage to the #2 and #1 bearings and breakage of the top rings of the #2 and #2 pistons, which in turn put a small "scratch" in the #2 and #3 cylinder walls - thus screwing my half-million mile engine until I feel like getting the bores cleaned up and getting the crank bearing-think taken care of.

Any alternate ideas as to the death of my B18?