Air ride suspension kits for the 1973-87 Chevy C10/20/30 Square Body Trucks and Blazers.  These are gonna be bolt on in front and weld on rear.  Depending how low you want to the truck and how tall your wheel tire package is you may want to add Drop Spindles, Weld in Notch, and some kind of Link System on the rear.  Check out the rear kit by Ekstensive

Finish your C10 air ride suspension with the Front Strong Arms by Ridetech

Not sure what kit you need?  Get more info here.