Lifted K10 steering pull

[1970Chevrolet]

Hey guys, I just picked up a new 1977 K10 this weekend that's sitting on 40s. I love this truck already. Drives pretty great. But there is one steering issue I'm a little concerned with. When I'm at highway speeds it drives straight even over bumps which is awesome, but if I start to turn it feels like it wants to pull that direction harder than it should. I noticed this first when I was taking it for a test drive when I went to pick it up. I kind of rocked the steering wheel left - right - left - right to feel how much play there was (not much) and it put the truck in a bit of a wobble to where I had to try and regain control because it kept wanting to pull kinda hard in each direction. Does anyone know what could be causing this and if there's anything I can do to reduce that pull? Here are some pics of the truck since everyone likes pictures...