Handling problem

I’ve had my 58 for 16 years and haven’t been able to correct a handling problem. When I turn the car either direction, It feels like the rear axle is steering in the opposite direction, resulting in huge oversteer. It’s bad enough that my friends are too scared to ride in it. I’ve had the front suspension rebuilt and aligned at two different shops. I replaced the front sway bar with an oversized one with polyurethane bushings. I had a seventh leaf added to the rear springs to stiffen them, replaced all bushings and added a rear sway bar. The power steering valve and the ram are rebuilt. The bias ply tires and all the shocks are new. Today I had a four wheel alignment done and a ball bearing kit installed on the idler arm to tighten the steering. I had a set of radials on for a few years and the problem seemed moderately worse.

Have you checked the body mounts to see if there are tight and that they have steel spacers not rubber.

Are the bushings in rear springs good ?
screw sway bars - add heavier shocks . Monroe magnum in rear if ya have ta
Toe in ; add another 1/16" to 1/8" total toe in max
36 psi tires max
Put tire on a Load force balancer to check directional stability . but decreasing down to 28 psi Should give you a clue .
new rubber bushings in cylinder ram ,both ends and not over tight
Snap pin (not broke ) and ball stud /snap pin cap not too loose or tight. < lots of travel here<:confused: