Sensitive Steering

[BigRed63]

Hey all,
I am brand new here and this is my first post and I wish I would have found this forum about 2wks ago, you guys have great information. Anyways I recently purchased a 63 C10 step side long bed with updates from an 84 Silerado, rear axel(3.73), front disc brakes, and power steering box & pump. I am by no means a mechanic but I do like to do my own basic maintenance. Ever since I've had it the steering is very sensitive, not sloppy but very easy to turn... too easy. It's not a big deal at low speeds but when I get up to 50 or higher it feels like I could easily over correct. The steering box had a leak so I have replaced it and from other suggestions I put in a Borgeson power steering reducer, but it hasn't seemed to help. Does anyone have any other suggestions on what I could do to get more resistance on my steering?