Awhile ago there was the idea to use a later B-Body (I think?) LCA and steering arm. This setup has the LBJ in the arm and the steering arm is a bolt on. Unfortunately, this doesn't really invert the LBJ location and I doubt would improve the KPI.
The 73/74 B body LCA does a couple of things, but no it doesn’t do anything to improve SAI/KPI. Depending on the version it uses a screw in or press in lower ball joint, which isn’t an A-body specific part. Howe makes ball joints that fit those arms, so you introduce rebuildable lower ball joints that can have the studs exchanged for different heights or tapers. That gives you more flexibility with altering geometry or even changing spindles.
The other thing it does is increase the clearance between the LCA and frame, so, more suspension travel. You can’t necessarily use it for travel unless you also raise the inner fenders, but you could return to using a more progressive bump stop vs a thing poly stop.
And if you did decide to alter the steering arm geometry you could modify one set of steering arms, and you wouldn’t be stuck doing it again when the ball joint wears out because they’re separate parts.