Death Wobble

[79c25]

So today I decided to get some work done on my K5. I replaced the brake pads and since the front tires were off I did a rotation. I made sure that everything was tight and went to town, no problems. On the way home the truck decided it wanted to dance going 40mph and it's stopped at 35mph. When I got home I double checked the lug nuts and the axle nuts, everything is tight and if I lift it up in the air I can't move the wheels by hand (side to side). I'm thinking that the spring bolts might need tightened up, would that cause a death wobble, or am I missing something here? Front axle is an 8 lug 10 bolt with 33 12.50 r 15 bolted to them.