Hahah, we were on similar missions that day
I was doing the same thing, except I was loaded with 40 16x16 flat cement stones weighing 36 lbs each
I love this truck, I was way above the recommended weight limit and the thing still felt like there was barely anything back there. GM ftw.
I used to load up my 89 tho, but that wasn't such a good idea.
One load from Sam'* Club up in wisconsin and the back looked like it had another car in it
Had to drive it 40 miles like that, hitting the bump stop every 2 seconds