A 1974 Duster - My 2nd one, 41 years later!
How I did my fiberglass bumper to car mounts. Of course this was just the way I came up with, you can do it anyway you want. First remove all parts of the shock absorber OEM bumper mounts. With a piece of 2" wide, 3/16" thick steel bought at Home Depot, I cut four 4" pieces (two for each side) and welded them together at 90 degrees. The outside slot was put right in the center, the inside slot was 3/4" from the top, see pics. Outside slots are for side to side adjustment, inside slots in/out adjustment.
IMG_4699 by Alexl5280, on Flickr
IMG_4700 by Alexl5280, on Flickr
IMG_4698 by Alexl5280, on Flickr
IMG_4697 by Alexl5280, on Flickr
How I did my fiberglass bumper to car mounts. Of course this was just the way I came up with, you can do it anyway you want. First remove all parts of the shock absorber OEM bumper mounts. With a piece of 2" wide, 3/16" thick steel bought at Home Depot, I cut four 4" pieces (two for each side) and welded them together at 90 degrees. The outside slot was put right in the center, the inside slot was 3/4" from the top, see pics. Outside slots are for side to side adjustment, inside slots in/out adjustment.