[wadesdad]

I ran into a similar situation with my A&C. My mounts were 3/4" off on both sides. I made spacer blocks from a scrap 3/4" piece of steel to fill the voids.

Before you land on a solution see where you'd like to place the engine - centered or offset. It is not uncommon in hotrods for engines to sit slightly to the passenger side to offset driver weight and/or to provide room for the steering column.

I chose centered, however.

Good luck.