Originally Posted by topside
Yeah, agreed - spring rate would need to be spec'd, and the narrower spring would arguably work harder, it was just a thought for a cheap way to gain clearance.
It avoids modifying the rear axle perches.
Many times, 1/2" makes all the difference...and yes, I realize that's a set-up line for a wisecrack, which I would reply with myself laugh2

Dr Diff has a 1/2" kit, but I'd assume re-drilling is required for the axle's spring perches.
I've previously found that the MP 3/4" kit doesn't really do much, but A-bodies are always dimensionally "casual" around the rear wheel openings.
All of mine have been tighter on the right than the left, from 1970 to 1974 so far.
Of course, the real cure is the "nuclear option" of the 2" deal, cutting the rails, welding in front boxes, and "while you're there", mini-tubs & narrowing the rear axle.
But that's beyond the budget/time/whatever for a lot of folks.


The Dr diff kit listed above is at least honest about the clearance it provides even calling out the incorrect excessive claim of .75" Mopar Perf claims for their kit. Either kit does require some drilling into the frame rail to accommodate the welded-on nut of the front hanger and removal of the OEM perch and re welding a new set on. Just stating this- with everything installed and the new perches on and the U bolts clamped down to spec someone could weld the new perches to the axle tube very easily. If one is not a welder the car could be driven to a shop or if it's a non-road legal race car a mobile welder could stop out and lay a bead on the new perches.

Last edited by 2boltmain; 04/15/24 05:50 AM.
Keep old mopars alive.