'little help on rear spring

I'm in the process of setting up the rear suspension on my '33 fenderless pickup. I would like to use these mono springs I have in a parallel setup.
The springs are 2" wide 7/16" at the thickest point and are 42" long. They were removed from I think a Geo or some other fwd compact. (I used the axle to get my cement mixer rolling). I can stand on these springs and they flex considerably. I'm thinking they would offer a pretty cushy ride if they would hold up OK and not break or something. Also, thinking I could add a leaf or two in the future if they seemed too soft. Thanks for all response.

Facts to consider:
rear of frame is boxed W/ 1/4" plate
17g. fuel tank
radiator in bed
Ford 8.8
Flathead power

 

I think your gonna need some type of torque arm, a mono leaf in a parallel set up is gonna have alot of spring wrap, especially something that soft. If it doesnt work well it would be easy enough to swap in a different set of springs though.