So, I guess 3/8" bolts are insufficient to anchor my frame to the other frame. While they lasted 50 hours, the replacement lasted 5 minutes. To avoid having to pull the engine off it's frame, and then take the lower frame out and drill the I beams from their backsides, I'm looking for some some sort of drill, chuck, gearhead, 90deg air drive drill motor, something, that I can drill in place, up to 7/16" . The rail width on the I beam is not large enough to get 1/2" bolts in, but I think 7/16 would do it.
Any opinions if 3/8" is too small to hold the load, did I get a couple of duds ? Would 7/16 be enough to hold the frame (not the crankcase) of a 6/1