Your car has a high 10 in it, I assure you.
Specifically, stock A-body shocks will never work with SS springs. Those shocks with extensions, or a C-body shock MIGHT work, but you really need a shock that get to at least 50/50 valving.
I wouldn't change ONE thing until I get it to hook. Then I would consider the relationship between the low gear set and a "redone" converter that wasn't "redone" to YOUR combination.
I'll say one more thing, if I had this car and ran those numbers in the Bakersfield early Sept "air", through the muffs...basically street trim...I'd be pretty happy.