this is a 54 but you still have to modify the right side of the bracket for how the dash slopes down around the key area
test it, and when it fits flat against the firewall and up against the bottom of the dash you mark it with a marker through the booster holes.
once you have your marks, measure UP one inch and make your marks again. this is because the 5 degree booster plate will rotate the mount up the firewall about that much. I guess I didnt take a pic of that yet, I will tomorrow. the sun was going down.