http://www.hotrodsandhemis.com/Traction.html
Now after reading this article , at least I understand how they are supposed to work.
Some good info in there and it shows why most slapper bars are a bad idea...if they are not cut to fit exactly, which most guys don't do, they tend to hit the spring right at its weakest point. If you can adjust them to hit right under the spring eye, then they can be effective, but their low ride height can cause clearance issues with speed bumps and curb cuts and hope you ever have a flat tire with those as could potentially dig right into the pavement dependign on rim size and tire aspect ratio.
It also shows why the Cal-Trac is effective. The bell-crank piece in the design is a dynamic spring shortening device. As it rotates, it changes the force intersect point from the spring eye to the point 6" back from the, creating an effectively shorter front segment. This, in theory, creates a dynamic version of the original mopar SS spring design. Cal-Tracs were developed by a Mustang racer who was rules limited by his class to retain the stock mounting points, yet he was trying to devise a way to create the more rigid front segment in his symetrical Ford design that would mimmick the asymetrical design of the mopar leaf.
So, the first thing you should try is getting some basic leaf spring clamps from you local parts house, and adding these to the front segment to stiffen it up. If this is effective, then you can look at ways to achieve your ride height while getting rid of the air shocks. In most cases, this can be done by adding a leaf to your pack. I'd suggest using a full length leaf just under the main leaf. Get a regular main leaf and cut the eyes off. This allows you to set this second leaf tip to align with the front spring eye, thus reinforcing a known weak area, while improving rate to avoid hop, and providing lift to the ride height.
