i can explain a bit but dont know how much help it will be. i have both set-ups. the power pitman arm is different from the manual as the shafts are different. as im told you are experiencing the difference. i believe if you switch to the power steering box it will solve the problem. i will check on the boxes to see what numbers they are. i have a 68 and 69 power box and a 67 and 68 manual box. the 68 box should work for your application. i'll the numbers on it tomorrow as i will be in the garage then. garage is across town or i'd get it now!