8 3/4 U Bolts

Not the same car but my 72 Demon with an 8 3/4 rear is 1/2" fine thread. 7" long leaving 1 1/2" below the nut under the shock plates. They were replacements when I put in new leaf springs with no flattened area on top. Not sure the flat part is needed unless you want to keep it looking origional.
YOTE