[deuce_roadster]

I have a 4 way battery cable terminal cleaner (cleans inside of cable and outside of posts) that has on one end a tapered reamer that may remove enough material to let the cable go down farther on your post. It looks like there is room for it to go down. You could also mill off a little bit of the top of the clamp as that would remove the smallest diameter part of the tapered hole. Every little bit helps.