When (if) you pull the pan and oil pump, look at the plastic coupling sleeve on the shaft...is it there? (or was it what came apart, and made those shavings?) I also like 31Vicky's synopsis: plastic teeth from timing gear. (seen MANY of those stripped at teardown!) Once, I tore down a 350 and found 2 or 3 amber colored 'chunks' of medium-hard plastic. Beat my brains for a few minutes, then deduced they were parts of someone's plastic hammer that had been used to pound God-knows-what in the bottom end. (???)
When it was still ticking...you could have pulled the distributor and spun the oil pump with a drill to see it it made the ticking noise without the engine running. Just an idea for the future.
That coupling is something like a comp 6/6 nylon, quite possibly the culprit. I've found odd undamaged sheet metal screws, a gl*** marble and once the head of a main cap bolt in oil pans. Bob
Yup , drove it all over today and never missed a beat , soooooo Im gonna take the first option . Change the oil a few times , continue to beat on that small block like a red headed step child and then if she does go **** this summer , ill peel it out and stack up another small block with a little more go fast to it.