m i have driven my 72 road runner, was 624 now 572 hemi with shumacher conversion mounts 50,000+ miles with 1/4" shims between the k member and the frame rails without significant problems. i have moog offset A arm bushings to get 3* positive caster, and i corrected the driveshaft angles before i drove it anywhere. the torsion bars slide in and out of there mounts without problems.
the only problem i have is a mild bump steer on large bumps at speed, like potholes. i mostly drive highway miles, was daily driver for 8 years. if you plan on cornering you probably won't want shims.