If there is a secret to Calvert’s success, it’s likely the suspension package. How else can you explain a little 9-inch tired car winning so many rounds against much larger odds? Included are 9.00 X 30-inch Firestone slicks (standard stock eliminator pieces), Center Line Convo Pro wheels, Koni shocks on the nose, Griggs Racing shocks on the back, heavy duty FoMoCo leaf springs and a set of Cal-Tracs traction bars. Herein lies the secret: Calvert and close associate, Larry Kieser developed a traction bar that would help hook a stock eliminator car under the letter of the rules. In short, it had to bolt on a leaf-spring car and had to be easily adjusted. What they eventually came up with is a bar that bolts to the front spring eye location and the bottom of the rear axle in place of the stock spring seat.
		This pivot arrangement is mounted at the front of the Cal-Tracs bar. When installed, it mounts over the top of the leaf spring pack. In operation it forces down on the leaf. A conventional slapper bar primarily stops leaf wrap up. Calvert claims it moves the chassis instant center (I/C) ahead, which allows the car to pick up weight in a location closer to the front end and transfer it to the back wheels.
When you take a look under the front pivot you can see the chrome moly lower link. A rod end is incorporated at this location, along with “wrenching flats” on the lower link for ease of adjustment. Left and right hand rod ends are used at both the front and rear. This means that you can easily adjust the overall length of the lower link using the wrench flats. This particular adjustment allows you to add preload into the suspension. Preload on the passenger side is usually necessary because the twisting forces created by the engine tend to lift that wheel, not plant		In operation, the bar changes the “pushing forces” on the car (when compared to a slapper bar). Instead of simply preventing spring wrap-up, the bar is much like the lower half of a 4-link. According to Calvert, it moves the chassis instant center (I/C) ahead, which allows the car to pick up weight in a location closer to the front end and transfer it to the back wheels.

In practice, a front pivot design acts around the front spring eye and loads with a down-force on the front portion of the leaf spring. As the rearend rotates, a forward motion is developed, which pushes forward on the pivot and forward on the body, not up as is the case with slapper bars. In the end, pinion angle is maintained and the car hooks. What you get is a car with less body separation than a slapper bar, but with more weight transfer. The bars offer complete adjustability and can be pre-loaded if necessary (just like a 4-link).

With the load bolt on top of the spring pack, then the system acts like a 4-link. The upper link consists of the spring and the load bolt. Meanwhile, the lower bar acts like the lower link on a 4-link system. The front pivot design acts around the front spring eye and loads with a down force on the front section of the leaf spring. When you drop the hammer, the rearend rotates. Then a motion is developed which pushes forward on the pivot and forward on the body. This is in direct contrast to a slapper bar, which pushes up, not forward.

And just like a sophisticated 4-link suspension, the bars used on Calvert’s car (Cal-Tracs) allow for easy adjustment. The bars can be moved for more pre-load and they include a pair of forward mount holes. By moving the force link bar to the lower mount location, the instant center moves further forward. This means that very nose heavy applications can still be made to transfer weight to the rear (and consequently hook).