75 to 73 Duster bumpers

The 5 MPH bumpers and mounts weigh a ton compared to the older stuff. I just picked up a car from my brother. It is a 75 Duster. Before I got it he put a 72 Demon front end on it. The bumper mounts are different so he just welded the 72 Demon mounts on to the frame. It looks good and works but I want them bolted on. So I am driling the mounting holes in the frame using the brackets as a guide then put in bolts. There are holes in the frame where the bolts go in that I can put the nuts up through.


I know the Demon/Duster front ends are not the same, but they cant be that far off?