Frank, you are correct about the wheel cylinder mounting. I didn't look close enough when I checked on RockAuto for the wheel cylinders. Does the rear anchor pin that's separate from the wheel cylinder mounting use a 15/16" hex nut?
It seems like that front anchor pin mount would actually restrict the ability for it to move in relation to the backing plate. The hole in the '51 backing plate is elongated vertically to allow the anchor pin to move.
BTW, RockAuto has AC Delco wheel cylinders for about $12 each.
