update
starting to mock some things up, before and after
small notch in the frame to get rough placement of things.
axle back underneath
moved the axle from below the spring to above the spring
and the start on the frame Z
another view.
connecting the stacked frame...
does not look like they are using a shackle ?
seems like that setup would bind, but maybe there is not much suspension travel.
best alternate angle I could find:
building up a rig and wanted to tap into the knowledge here to get some advice.
its a truck frame with a parallel leaf front axle, and was thinking of going with a quarter elliptical spring setup.
either equal length spring and control arm setup, like a 4 bar where one "bar" is the spring...