Exhaust and disk brake conversion
Truck Parts and Truck Accessories
They also have a drop suspension that'll lower you 3" in the front and 4" in the back, but I think you're wanting to go lower. For the EFI, there's a couple of bolt-on EFI's that replace the carb that will tune themselves. Edelbrock, Holley, MSD and Fast all have a drop in, don't personally know anyone using them, but have read good things on all.