Finally figured out how the stock jag suspension worked....I think.
It pivoted on the lower half of the spring pin. The upper half was mounted in rubber such that the pin couldn't catch anything. as the spring cycled, the top portion of the spring pack could move front to back.
Here is my attempt to immitate the function.
more almost free material was used for my spring boxes. ....cop car roll bars that dad bought at an auction. I used the 1/8" panel at the bottom.
I overlapped the tops so I'd have double thickness on top.
The insert captures the spring pin. It is secured by four 3/8" bolts and really beefs up the spring box when it is all bolted tight.