Left Disc DRAGS...??????

My Duster does the same thing, 70 factory manual disk, changed to 73 set up, late model aluminum master, 70 prop valve. When the front is jacked up the wheels will go maybe 1 turn before they stop. When i really get on the throttle, she wants to pull to the left. But she will roll down a slight decline with no problem & no pulling. She also has 90/10's on the front but I don't think that is the problem. I've rebuilt the calipers twice, & made sure the slide area is well lubed with antiseize. Do you guys think the prop valve might be bad & sticking? When switched to the 73 stuff all the lines got changed out as well. I'm running dot5 brake fluid as well. Thanks inadvance for any help, Russell