Roo,
I dug around too a little because of the slots in the torsion arms, came across a Kellison Catolog and the pic shows a center axle radious rod for which the chassie that Blaze shows also has the mount on the torsion. That would allow the slots in the arms ,but the original Kellison arms were curved to clear the spindal ty-rod. Would like to see the back of the chassie to see if it has 2 rear uprites or 1.