So I repaired my frame about 2 years ago. Bought a Bronco Designs tub and started cursing cause I couldn't bolt it down. So I had the body just laid on there while I did other things. Today I took it off and using string, a square and a measuring tape, I found that the aft 2 mounts are near perfect width-wise, but are 1/4" forward each (according to the BMP frame file I found on here). The next 2 mounts forward are 1/8" inboard each. What a pain. Now I have to mess with this again on a powdercoated frame. ugh.