You could have problems with the power assist cylinder or the control valve. (haven't run into many pump problems, others may help you)
Getting older just means you deserve comfort.
I had completely redone ALL of the Steering components at the time of resto (as normal) spent time setting it to its best, but still just didn't have that feeling I was after. I had the Steeriods on the shelf...but wanted to perfect the steering for future info...anyways I decided to change the steering to see what difference it would make in comparision to a good working stock system.
With that said I just install a Steeriods system had a small length problem with the intermediate shaft nothing serious and I was apparently the first one to have this problem (there is a thread here at C3VR STEERIODS RACK), Steeriods is making me a longer shaft anyways, Once you install Steeriods you will wonder how you drove your Baby with the stock system...many of us will tell you the difference but once you have driven with the new system...the handling is an unbelievable difference that only you can experience, you do use your existing P/S pump everthing is included for a complete bolt on replacement, not hard to do, just takes a bit of time, about 5hrs.
As for the steering effort...it is effortless, handles bbbbbeautiful, I couldn't say enough about the joy of driving the 72 vette.
Hope this helps
John