I just did this myself on my '72. Ideally you use a press to handle the lower ball joint removal and installation. The giant "C" clamp thing/free tool rental was a bear to use even with a 450lb impact wrench. Remove the bushings from the control arms or at least loosen them after you take the springs out but while they're still on the truck. You'll need an air hammer and rivet cutter to replace the upper ball joins or a center punch and a careful/steady drill hand. At some point GM replaced the stock U bolts with heavier duty ones which are still stocked at the dealers. I purchased my whole front end rebuild kit from Early Classic. They're great to deal with.
Then I tackled the rear leaf springs...yow.
All good now.