The holes in the A body engine mount brackets should orient the biscuit to the front of the bracket. If the holes are near the rear of bracket, they are B/E body brackets.
On the left is the A body driver side 340/360 mount
The 340 mounts require no washers or spacers of any kind on a production 360 block. 360 block drivers side mount ear spacing is the same as a 340.
