Like AJ/FormS said, it's a trial thing. It takes some time to get it where you like & depends on some things like steering wheel diameter, (mine was the stock plain Jane Duster one) & tire size. I had the room & did this mod right on the car but again, again, it takes time to do. Draining the P/S fluid, removing the hose end, removing the valve & carefully disassembling it etc. It takes time but, I got lucky by adding just 1 shim, I used the copper crush washers that go between the brake hose & caliper on disc brake cars (I think most older American cars are pretty much the same O.D. but thickness may vary a bit. I had them laying around & fit perfectly. I got this trick from Mopar Action (Now recently de-funked) years ago. There may still be an article on the web about how to do this. It was called "Pump it Down".