Between A, B, and E bodies, I can see advantages and disadvantages that each one might have but it's unclear which set of attributes comes out with the best formula.

Regarding stock or stock-ish classic Mopars, I'd look to the B-Body ('68-'70 in particular) as probably has the best mix. It has the better (stiffer?) chassis than the A-Body and generally more room for tires, heavier duty OEM equipment and the stability from the longer wheelbase which seems to be a big help in many road course situations while giving up no real weight advantage (if any) to the stockier otherwise similarly massive, similarly equipped E-bodies.

Assuming that we're sticking with a stock style torsion bar front end/leaf spring rear, and building an otherwise optimized protouring car, I'd suspect a toss-up between the 108" A-body coupes and the 111" Darts, beating out the B-Bodies thanks to being significantly lighter while having essentially the same suspension. The Duster/Demon/Sport coupes have quite a bit more room for rear rubber and (IIRC) tend to be a bit lighter...but again, the longer wheelbase tends to be a boon to stability.

What do you guys think? Any thoughts (and corrections to my assumptions) are very welcome.