Reminds me of my '69 Ranger. it had an honest to goodness 390. Lots of power and torque. It had the same rear spring shackle set-up. I believe it was called Easy Ride. It gave the ride of a lighter spring but once loaded you still had the load capacity of a normal spring set-up.
1981 F 150 Custom 300 ci with a fully rebuilt 1968 240 head Carter YFA T-18 3.25 9" rear 2WD
dual gas tanks
1990 Lincoln Town Car 5.0 AOD
Home town Mc Kenzie, TN