Leaf springs and what to buy!

What is your primary usage for this car? If it's primarily a street car I'd be more inclined to use the Mopar Performance HD resto springs, or something from eatondetroitspring.com. or ESPO springs. They will tweak springs if you want for more or less arch. The S/S springs can be kinda stiff for everyday street use in my opinion.

Regardless, throw those extended shackles in the trash. You don't want to be riding around in an unsafe clown car.

Your front spring hangers are good but depending on which springs you use, be prepared to drill the through holes to 5/8" diameter. (The Mopar S/S springs for instance use 5/8" dia bolts.) I've measured 9/16" and 1/2" thru bolts on stock a-body Mopar springs. There are front adjustable hangers out there. Off the top of my head, check ARengineering.com if you want to play with ride height.

The stock frame mounted rear spring hangers are perfectly fine but get a pair of stock shackles and if you want an improvement over that, replace the bushings in the shackles with poly.

Take a look at the Mancini Racing site too.