Everyone I ever talked to said they were just window dressing on a Mopar with s/s springs due to the snubber and the springs being designed with more leaves on the right side to handle torque. They were great on Camaros and Mustangs that were designed differently. I think Bill "Grumpy" Jenkins was credited for coming up with the first set. I am not sure that I ever remember seeing a Mopar drag car with traction bars back in the day. They are a fair chunk of weight if they provide no benefit to your setup otherwise. My 67 GTX had a set of Lakewood slappers on it when I bought it and removing them and selling them to a guy building a Chevy S10 pickup was one of the first things I did. The guy I bought the car from just liked the look, but I though they screamed "poser" on a basically stock drive train.