Stiff steering ?

My 92 Supra Comp steering is very stiff while underway. On the lift, or at idle in gear it is ok, but once underway, it is a two hand effort to make turns?
I have had Centurion's, Malibu's, and Moomba's and could steer them with 1 finger, but not this Supra.
This is my first season with this boat and I am sure everything is original?
Would a "old steering cable" feel free ( not 1 finger free) under no load and stiff underway? It has a new 4 blade Acme on it, but there was no difference in the old OJ 3 blade.
I have yet to disconnect it from the rudder because its out on the lift.
Looking for any hints or common steering issues with these older boats?

Check the rudder port.

I checked the rudder while it was on the lift today. There is slop side to side and front to back so I will try to repair it at my next chance.
Do you happen to know if a 92 Supra would be a cord type packing or if it was the tap in seals and grease fitting? It would be nice to have it ready before I tear in to it, so as to cut some of the down time.
Also, I was able to turn the rudder side to side easily from in the water so I think the cable is ok for now.
Thanks again Michael.