A previous owner would have had to have done it or perhaps a mechanic, no Chevy 6 cylinder crank was ever drilled from the factory. Even the Stovebolts going back to 1937 or 38 were not drill either.
Not to mention that stovebolts through '53 all had provision for hand crank starting on the crank pulley snout (even though there was no opening in the grill to support inserting a hand crank). One needs to grind these 'ears' off of the snout before fitting a flat washer and retaining bolt.
