55.2-59 1955-59 Chevy 4x4 Power steering problems

[1957Napcofan]

I have a 56 Chevy 4x4 with the stock frame and using the CPP 400 Power steering box. Have a GM 10 bolt front axle with brackets welded to allow stock shock location. I used a late 70's Ford F250 steering arm. Truck is just about undrivable with this setup. Will not track and has way too much play. Also using a double steering stabilizer. New ball joints, tie rods, steering arm. Truck tracks straight down the road when you follow it and thrust angle is good on the rear axle.Toe is about a 1/8" Camber 1 deg and Caster is 6 degs. From other forums I found that most guys that are running a GM 10 bolt or Dana 44 prefer 6 degs.

When you turn the steering back and forth the steering arm goes up and down hill so the drag link from the pitman arm does not stay level. Could this be the
problem. At a loss to what else to check. Wheel bearings are not loose, don't see any play in the linkage. Really stuck and need help.