Yes, I did it.  I butchered a perfectly good, rotted out, 6 cylinder, bondoed up, real convertable, mustang, into a 4x4 beast on 40" tires.  The car wasnt in very good shape to begin with, it had tar paper floors and rotted subframes.  It wasnt fixable, because if it was, I would have built it into a street car.  But anyway, its done and i cant reverse it.  The running gear is a 76 Bronco.  You know, the boxy mini fullsize ones.  I had to lengthen the frame about 16 inches to get it to fit, but the width was perfect.  It is outfitted with a bone stock 302, headman headers, glasspacks, race tranny, lincoln locker in the rear, 3.50 gears and ladderbars.  The 40s are gumbo monster mudders, which are about half tread and less.  it goes real good, but I need a better engine.