Does mono leaf really ride that bad?
Also where is the best place to buy the shackles and pins to mount the leafs front and rear
If you are looking for standard shackles and pins/bolts/bushings, most reproduction parts vendors sell them (Jim Carter, Classic Parts, Chevs of the 40s, American Classic, etc).
Eaton Detroit Springs, ESPO Springs & Things, and maybe local spring shops should sell them, too.