Thank you everyone for your help. The links and summaries given are terrific, thanks. Sorry i didn't say so sooner, but finally have the time to answer. It does answer some questions.
Just one thing that is still confusing me... the block casting has M38, decoding to Dec 3, 1978, or so I think, and discussed here before, but the stamping is as noted probably 1980. Could this block have been cast in '78, but not assembled into a replacement engine until '80?
