1966 GMC Rear Bumper Installation Issues

[BFoley]

I am finally Getting around to finally install a repro bumper and cannot for the life of me find any good pics/resources on the placement. The truck has several bolt holes (two 1/2" and one 1 1/4") on the frame rails that were used to attached an incredibly stout one-off bumper that I removed this past summer. I purchased the bumper and brackets from LMC and nothing seems to match up.

I have scoured the internet trying to find good pictures of bracket placement but am coming up empty-handed. Whether adding a bumper to a truck without one now or back in '66, were holes required to be drilled? If not, can anyone look at my pictures and let me know what is up? Also, if anyone can snap some pics of their installed brackets, I would be beyond grateful.








Thanks,
Ben