72 GMC rear bumper brackets mount at an angle??
 

Do the rear bumper brackets mount at an angle or just lay flat in the frame rail? I have the chrome sport bumper. It's not a step bumper.

Angle.

front of the bracket up.

The 4 sport bumper brackets (2, inner) go straight out in-line with the frame rails and then bend 90 deg. and rest flat parellel to the bumper. The outer brackets (2) bolt flat against the inner brackets and then bend outward at a 45 deg. angle and go toward the outer bumper bolt holes they then bend once more to rest flat against the bumper. I found that they are not an exact fit so you may have to "tweek them a bit" (the out brackets). One thing I've found is be VERY careful tightening the bumper bolts as you can wind up bending the bumper bolt hole locations (on the bumper itself, front one also) as the metal on the bumpers is a LOT softer than I first anticipated. Hope this helps, Doug

I looked at a Chevy rear bumper bracket with the same bumper as mine and the inner (longer) bumper brackets were mounted at an angle.

Hmmm, I've never seen that before (for a sport bumper). Do you have a LMC truck parts catalog? It shows it quite clearly, I don't have a pic from it but maybe someone will post one. Doug