275/60/15 sidewall clearance to leaf spring clamps- suggestions?

Actually a lot of people run 275’s on Dusters/Demons/Dart Sports. With the right backspacing they work fine on most cars in those bodystyles.

Problem here is the 4.5” backspace is what you need for an A-body 8 3/4 with BBP axles, which is too much backspace for the narrower 8.25”
Correct you are. I wasn't paying close enough attention to what the op was driving. I'm always in Dart mode.