In 1968, while living in Anderson SC. i had a customer come to me with traction problems with a 1966 Camero conv. He had a 427" with a clutch turbo 400 running 10.5 M@H tires 4.56 gear 12 bolt had to weigh 3520 lbs. for the class. The engine was built by a guy in Fla. I don't exactly remember his name but i think it was Art Carr and we was running B/MOD production. His name was Jim Little, the car was called little by little.
Anyway i built a set of slapper bars out of 2X3 rec, tubing, very similar to what you are seeing, useing a rubber bumper on the front at the spring eye, but i did one more thing i extended the bar to about 8" behind the axle and put a sq. ubolt to limit the spring wind up, i left about 1" clearance/travel before the ubolt would start limiting the windup (if you remember in those days Chrysler had a pinion snubber) Anyway the car had such a big cam it would bog unless we came out at 5500 or above. I maintained and tuned the car for about a yr., The car would run 10.91 @ 127 mph. The national record was 10.89@126. I could never get the car to run the ET but was well over the MPH record. We won every race we went too, including the first ever national event race at Rockingham, SC. The car was deadly consistent and would pull the front end about 18" every pass. Slapper bars do work in the right situation.
This was a monoleaf car.
JMO
Zip.