I have seen spring pin failures on a distributor drive, but not on a Chevy engine. The same Ford 300 engine sheared a spring pin twice within a couple of months. After the second failure, I pulled the oil pan and found that the sump had a lot of debris in it from a failing timing gear. The teeth had a plastic coating on them that was breaking down into granules about the size of a match head. The oil pump pickup screen also had holes in the mesh strainer big enough for those pieces to get sucked into the oil pump.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!