'68 Short Step....What's wrong with the steering?

[MotorSeven]

Ok gang, it's been awhile, but the truck is off the blocks for the first time in a year. I did a front crossmember swap with a mid 70's c-10 w/power steering. I put rallys & new tires, bearings,calipers,pads on & am having trouble with the steering. There is what i can describe as a "tight spot" around center, & once past it the steering gets easier. This occurs in both directions & causes a herky jerk as i go down the road. It's really fun when my foot is in the Holley because it is accentuated at speed & in curves.
So, i have no clue where to begin.....ball joints, steering knuckles, gear box??? Any help is appreciated.........

RD