A 1974 Duster - My 2nd one, 41 years later!
I drilled a slotted hole in the center of the bumper (will be hidden by license plate) so I could hang the bumper and get it close to where it will live. This way I can figure out just where the 3rd plate goes, I made a black sharpie line on the bumper in the center of the OEM shock mount hole. Then welded the 3rd plate centered on that line.
IMG_4703 by
Alexl5280, on Flickr
Brackets on bumper. 2" by 3/16" pieces of steel welded to "c" metal.
IMG_4702 by
Alexl5280, on Flickr
IMG_4701 by
Alexl5280, on Flickr
This is the angle of the 1" by 3/16" steel that brings the mount through the OEM bumper shock hole. The piece is 6 3/8" long, not sure of the exact angle. I started chopping the angle until it fit onto the plate and went through the center of the OEM shock bumper hole. Then as you can see in pic two, I welded another 4" piece of 1" by 3/16" to the bottom of the angled piece. Then cut the slots for up/down adjustment.
IMG_4704 by
Alexl5280, on Flickr
I'll be powder coating the mounts in black.
The rear bumper with the steel mounts weighs 12.35 lbs.