Trailer Sway Help

[taylorbg]

I pulled the boat for the first time with my 1972 4x4 Suburban. I ended up having a lot of sway once I hit about 55 mph. Slowed down under that and it went away instantly. I bought this truck in November, so it is new to me. This is also my first experience with a 4x4, larger tires, and possibly a lift.

It looks to me as though there is a lift, but I do not know the size if there is, or if that would affect the swaying issues. The tire size are 33x12.5 R15.

I do have a lot of play in the steering and am looking into getting new Redhead steering box. Maybe that is the issue?

Another thing I thought about, could it be that I need a larger drop ball for the receiver hitch? Maybe the front of the boat is too high, putting too much weight in the back?

Any ideas and pointer would be greatly appreciated. Here are some pictures.