Hitachi investment-cast BB shell. This is very interesting if the tubeset is actually 531 Red Label "Pro". and given the frame bits...might be an American Custom. the headlugs are very minimal, what some call "bikini lugs". subscribing for the updates!
EDIT: I did not notice the OP's location, will revise my guess to say "Australian Custom", but very likely a high-end frame wherever built.
Last edited by unworthy1; 10-31-20 at 09:37 PM.