[a.c.ward]

I have seen these helper springs installed on a couple of trucks, mostly longbed trucks that were used for towing and heavy loads. Only ever seen one set a short bed that suffered from sagging springs. Pretty commonly installed in the late 70's to get that "stink bug" tail high stance with oversize tires in the back.

Aftermarket replacement springs were not as common as they are now back then, and we did what we could afford to do, lol