I’ve run both the Bilstein RCD’s and the non-adjustable Hotchkis Fox shocks on my ‘74 Duster, and while they’re pretty close in performance I definitely give the edge to the Hotchkis Fox’s.
But I’d say it’s a small edge, and I think a lot of it has to do with that fact that I run 1.12” torsion bars. The Hotchkis shocks just have some additional range that allows them to deal with the larger bars better. With 1.03” bars I think the difference between the Bilsteins and the Hotchkis bars would be less noticeable, and it’s already a pretty small difference.
In addition to the 1.12” bars, my Duster also has a 340 (400+ ish hp), had a 4 speed and now has a 6 speed T56, SPC UCA’s, QA1 LCA’s, Hellwig front and rear sway bars, AFCO rear springs (120 lb/in), subframe connectors, torque boxes, j-bars, tubular radiator support, fully welded and reinforced K frame, and 275/35/18’s up front with 295/40/18’s out back.