RedShitbox

Hi all, so I have a 2000 GMC Sierra on 285/70r17's, and the stock keys are cranked all the way to fit them. I originally intended to just leave it at the harsh ride (which I dont really mind too much), the issue im more concerned about is catching a bit of airtime on dips in the road, and feeling/watching the truck try to walk off the road on rough roads. My question is what do i replace to help fix that issue? I thought id get on here and ask for others opinions. I dont think its the UCAs but i could be wrong, they are the stock ones but it doesnt seem like its hitting the bump stop. Truck sits level at 39" if that helps.