17" Magnum 500's

72,
Your 71 Ford truck has a harsher ride..............because it has stronger springs! It is a work horse designed to carry heavy loads. Apples to oranges comparison. And it seems you have a reading problem.
I said in post #44 that if the matching suspension components that are used with a 14" in wheel are used with the 17" wheel, the ride will be softer.

Drivers who have overinflated their tyres notice the ride is harsher, you feel the bumps more.
Air is compressible & the extra weight of air in the tyre is not able to compress as much from the road shocks...so you feel the bumps more. Exactly the same principle is involved with less air in the 17" wheel compared to the 14"wheel.