Using some math from a 1971 stock car guide that factors in weight distribution and suspension type, I came up with some figures for the ideal suspension of our Hemicuda.

It would need 1.26" to 1.28" torsion bars in the front and 230# to 260# leaf springs in the rear.

MOPAR made those back in the day as I found them listed in their circuit racing parts catalog of 1973, but would you know who makes them these days ?