>The heads of the Model T and Model A main bearing bolts are square
Unfortunatly, they are also 1/2" , on both the A and T.
Except when they are not square...
In any case, there was a wrench for the mains, with a different number...
(more than one in fact, the non-square bolts take a funky weird wrench..)
The other problem is the head bolts aren't 11/16 either, they are 3/8 or 7/16...
It's always possible they just plain screwed up making the wrench, accidently taking old stock that had a ford number in it from the forging dies. The wrench shape is fairly generic, and I can see it being used for making some other special purpose wrench...