Rear leaf springs and shocks

I did discover these after a bit of searching, that purport to give 2.5 inch lift over factory? Would they be an improvement over factory (aside from just in height) or would other options possibly be better? These seem quite cheap as well at around $185 per side.

1964 - 1976 Dart, Valiant / 1964 - 1969 Barracuda rear leaf spring with 2-1/2" lift using 5/8" front eye bolt, 6 leaf