Aluminum Bumper Brackets

Awe not so entirely on the 74 rule that all went to shock type brackets as I have a 74 Swinger that the front are still this type of bracket. I would be interested the set for the front depending on price like everyone else. My question is how will they hold up for a fiberglass bumper as far as vibration.

i'd say they should hold up just fine as they are much stronger then a fiberglass bumper. they should even make the fg bumper last longer as it wouldn't vibrate at all.