Before I bought Cal-Tracks I would spend the same money and buy the Assassin bars from Smith Race craft in Texas. Far more adjustable.
The Rube Goldberg of traction aids.
99% of the fastest leaf spring cars are using Cal-tacs.
'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.