Tire/spring clearance: why not...

...get 2" wide springs, bush them between the leaf & outer hanger with something that'll hold up, and gain 1/2" ?
Maybe Delrin or steel ? You'd probably have to lube them occasionally.
I would think ESPO or Eaton could do 2" leaf springs in a variety of spring rates - IIRC, that's an old Chevy width.
What am I missing with this idea, or oblivious to ?

Spring plate bolt hole spacing/ width? rear shackles / width? Also keep in mind IF your centering off the spring pin that 1/2" is now 1/4". To me it sounds like too much "rigging" for the potential problems and little gain

I agree !!

Do you have room for 1/2" spacers behind your wheels ??

Just spit-balling a way to increase clearance at the inside of the tire.
Got to thinking about it, though it doesn't apply to my current project.
Spring plates are basically inside the wheel & don't interfere with sidewalls.
Yes, the locating pin would need to be moved: drill new hole, weld up old hole.

Sounds like a lot of work to gain a 1/4" (or with a lot more effort a 1/2") more clearance between the tire sidewall and the leaf spring. Then add is the shorter life span of the narrower leaf spring and the other problems connected with the narrower springs, Up until sometime in the early 60s, all the Mopars came with 2" wide leaf springs, and Chrysler determined there were enough reasons to widen the leaf springs to warrant the expense of doing it across the entire line. Going backwards with engineering really doesn't make much sense to me.

Without looking into the costs, it may be cheaper to just move the current leaf springs to the inside of the frame and solve all the tire sidewall to leaf spring clearance issues completely. That effort has proven results.

Either some wheel spacers of the lesser of the two inboard relocation kits for Mopar leaf springs.
https://www.doctordiff.com/a-body-offset-spring-hanger-shackle-kit.html

Why not move the stock spring in to get the clearances you want

If doing this, you would have to step up the spring rate. 2" wide spring will have a softer rate in compression and roll compared to a 2.5" spring.

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

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.

I remember a car mag playing with a Chevy Nova. They ground clearance into its leaf springs to provide clearance to the tire side walls. 2 locations on each side clearanced. I'm not endorsing this but I'm sure they were not the first to do this.