The j arm hooks up from the steering arm on the driver's side, and accepts the drag link from the pitman arm. This is found on stock "push-pull" steering setups on solid axle rigs. Flipping the ball is a good modification because it is located on the bottom of the J arm, and even with mild lifting, the increased angle of the drag link puts strain on the ball. Flipping the ball to the top relieves much of this strain, and leaves less possibility of breakage. I wouldnt worry about histeer, unless you start lifting the front and experiencing bump-steer, but the J arm flip is worth considering if you are capable.