Yes, the Air Lift 1000 kit part # AL60755 that you referenced is a confirmed fit for your 1979 Buick Estate Wagon. Everything about this kit is the proper size and will fit well since it's been tested. view full answer...
I attached a picture of what I believe is your best option for a weight distribution shank that has at least 5 inches between the pin hole and the support gusset. The part number for this shank is # EQ90-02-4500. view full answer...