Now that is interesting. That "99A-" prefix translates to '39 Mercury SPECIFICALLY - (NOT Ford), and likely carries-over thru 1940 MERC. Sounds like the ball on the '39 & '40 Merc wishbones is somehow smaller than the same year Fords. I do know that '39-'40 Ford and Merc wishbones do not interchange, as the Merc 'bones are longer, front to rear because of the Merc's 4" longer wheelbase. That "11A-" prefix is a Ford prefix (fairly normal Ford Motor Co. numbering methodology when Ford & Merc DID share identical parts). That is likely telling me that Ford finally sized Ford & Merc balls similarly, and are probably the same thru the end of 1948 production......MAYBE! Coop
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