I just converted my 70 El Camino to power steering. I bought a used pump and the got the steering unit (4 turn)from my 69 Chevelle. I have had the truck running, and turned lock to lock and refilled the resivour. I have effortless steering turning left and hard turning right. It has gotten easier, but it still is very stiff, and ideas. The steering worked fine before the conversion. I'm baffled. What do you'all think. Thanks, Edd

You could still have air in the system. Drive it a bit a let it sit overnight.

Otherwise, you must have a problem in the power steering gear since you have power steering in one direction and not the other. The pump doesn't know which way you are turning.