Help me identify this brake drum

Oklacarcollecto said
That is exactly what I was thinking.

Further research yields:
http://www.racingjunk.com/Rear-Ends/182103050/Moser-Engineering-axles.html

These are for a Chevy, but the marking from the forging is the same.

The studs were probably trimmed to fit the lugs.

Moser used to sell these specifically to convert A-body axles to BBP