I took the ones off my 53 a couple of months ago. I thought I was going to be smart and used penetrating oil and wire brushed the bolt ends. A couple came off. Most of them spun and tore up the slot in the running board that now needs repaired. I was able to break a couple. Some of them I was able to cut the nuts with a 3" cut off wheel. The ones back in the corners of the mount I had to grind off with a carbide burr on a die grinder. In retrospect I should have probably just cut the ones that didn't easily come off and not damaged the running boards.
