Well, they work......not all that great as compared to the options, but they do work. The inherent problem with a leaf spring is that it will "wrap up" under load, the SSM bar is designed to limit the amount of wrap. Key word here being limit, not eliminate!!! Ideally, a single bar (per side) traction device on a leaf spring car should be the same length and travel in the same arc as the front 1/2 of the leaf spring. I guess the short answer is that yes, they do help but they certainly aren't the ideal setup for traction control.
I'll be running the leaf springs on my '57...though a repop set with the buttons in them which make the spring action much smoother. The rear suspension will also use a set of housing floaters and a 41" long pair of "period authentic" ladder bars. The combination of housing floaters and ladder bars take all the torque absorption (and resultant wrap up) out of the leafs. Their only function becomes a weight supporting function and more in line with what a leaf springs works best at.
Other things for consideration in your rear suspension planning should be the shocks and pinion angle. Lots of folks will insist that the pinion angle and transmission angle offset to 0 degrees, probably a good plan for street only applications. If you're going gasser style and running a ton of ground clearance then the driveshaft angle gets quite steep, and a pinion angle of 3 degrees down seems to work best...I know, scientifically this isn't correct but then I'm goin' racing, not cruizin' so my comprimises go to making the car "work" correctly on the track.... Also with a leaf spring car adjustable rear shocks become a great tuning aid for the suspension!!! I use AFCO shocks on almost everything I build, street or track. They are adjustable and easily rebuilt at home. Valving changes are simple and their tech support folks are second to none!!!!
Should I ever get caught up on customer work I'll be able to get going on fabbing up my rear suspension and plan on posting updates and pics as I go!!!!! Looking forward to the challenges presented by a gasser style car in getting the chassis and suspension to work right, launch hard and straight, high speed stability, and of course keeping "the look" of the components to match the era the car was originally raced in!!!!!
Rich, they are a traction bars that replace your U bolt/shock mount plate and instead of having a rubber snubber at the front, they solidly clamp to the leaf pack just aft of the front eye. I'll post pix of mine later today.
Ok traction bars, same ones on wifes camaro, thought you had something new, back in the day when I just about lived at sacramento raceway, I ran a `67 dart after a few months on the track I switched to a pinion snubber, and took off the tractions bars, first day out I redlighted 6 times before I finally used to it, man what a differance that made, mount right off the third member bolts mounted one inch below the body pan.