I couldn't get them to work with A-body SS 456/457 springs.

We went with split mono's and did a 1.38 60 ft. this weekend.

'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.