WTB Motor mounts
They are so close, unless you are doing a resto, you're better off just spacing the one bolt of the 318 brackets you already have.
The spacer trick only works on 318 to 340 B/E body mounts. The left 318 A body mount is missing an ear. And yes, you only need the left side. The right is the same.
Here's what it looks like if you try to put a left 318 mount on a 340 or 360:
here's the 340-360 mount
