My 73 parts car has an "H" axle code (2.73:1). So it's got the right speedo gear (luck!) I need for my 70. Maybe someday if I get ambitious I can make a twin-grip out of it.
But there's two stamps on the boss:
H
and beside it, rotated 90 degrees, in slightly smaller letters:
YH
Does this mean anything? Never saw this before.