1972 Ranchero frame

I would suggest making your front frame horns better, even if it means cutting those off and welding two different 72 parts onto it. The later(mid 73 on) frames are a much better choice, the 72 frame is made for a longer trans cross member. That older frame design requires the bolts for that cross member to go though the frame with a captured nut up inside the frame. Those always break now, and they are hell to get loose, get the bolts out. The later model frame like yours has a simple flange on the inside of the frame where a bolt with nut mounts a shorter cross member.

My two 73 frames are different, one has the old style trans cross member mount. I plan to sell the truck I put that frame under with the 73 front end. I'll use my late 73 frame for my keeper and the 72 front end.

The frame horns changed on all cars for 1973, that new 5mph impact mandate. So the 72 bumper bolts to the frame, and then 73+ the frames all have a rubber impact device bolted to the side of the frame front horns.

I did a fine job on my 73 frame, it's cut well enough the bumper only required one spacer on each side, if I recall right. There are some threads here where others did measure carefully and posted those and good pictures of the frame changes. I'd start there and see if you can figure out how close your 72 snouts fit to where they need to be.