I've about had it with this p/s on my 69 mustang. I would like to keep it but so far I have replaced everything, and most things twice. Too bad you can't buy original Ford parts anymore. The latest is the p/s pump leaks from the seal, a brand new Cardone (crap) rebuilt pump. I actually had them order 4 of them to get a decent one and then it worked for 250 miles and is now leaking. I really wanted to keep the p/s on this car but I'm on my last straw here. I have dealt with a seller on Epay called Chockostang before, real nice guy, and he's got a real nice looking pump, even has the right numbers. I am thinking of buying from him as a last resort, then I'm done.
The other issue is the slack in the control valve unit. I'm going to drive the car tomorrow and see if the control valve slack is something I can live with. I did make it better by adding caster to one side to make it pull to one side ever so slightly, it did help. If it's acceptable I might buy the chockostang pump.
The last resort will be taking the p/s off and adding a p/s to m/s converter, I've installed a bunch of them and they work quite well. If I do that I might add Hooker headers, as part of the reason I used cj exhaust manifolds was stock look, ease of use, and I did not want to use one of those p/s extension brackets on the slave cylinder.