Are you sure that's a 216 ? My 1951 216 has only one hole and the bell crank stud is screwed into it.

My 1954 261 has the two holes as yours does.The bell crank stud is screwed into the boss closest to the rear of block.I had to screw a plug in the other hole,I don't remember what size of bolt.

1951 3100 Chevrolet
1951 Chevrolet Suburban Carryall
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