Make Like a Tree FROM LADDER BAR TO STOCK SUSPENSION

If you travelled back to 1982 to report how quick a leaf spring drag cars are running in 2012, you would probably be burned at the stake for spewing gearhead blasphemy. Back then, if you wanted a super-quick 60 foot. out of your 1970s Nova, you had better plan on hacking it up and installing a ladder bar or four link suspension because you were limited if you wanted to run your factory leafs. But over the last decade, companies like Calvert Racing Suspensions have made hooking up your leaf spring muscle car a reality.

Here's a shot of Brian Adam's suspension before converting it over to run Calvert Racing's CalTracs and Split-Mono leaf springs.

The Calvert setup Adams went with includes the traction bars, leaf springs, hangers, and he even opted for AFCO's leaf spring sliders as well.

Brian Adams from Bischoff Racing Engines in Guilford, Indiana campaigns one clean Nova in the TREMEC True Street class, but in 2011, the NMCA officials made some changes in the rules that prohibit the use of ladder bars or aftermarket four link suspensions. Not being one to throw in the towel, Adams set out to convert his car to run stock suspension. The idea of true “stock suspension” posed a problem however: if he wanted to keep his car in the deep nines in the quarter mile, that meant he needed some form of traction device that will keep his tires firmly planted. “I contacted Gary Rohe Racecars for the conversion,” Adams said. “Gary has been building racecars for a long time and I knew he could handle the fabrication I needed to install the leafs.” When Adams bought the Nova from Jamie Stanton (yes, that Jamie Stanton), it had a 2 x 3 aftermarket frame. In the last few years Adams added the stock frame rails, but he needed the spring eye mounts in order to bolt on factory dimension leaf springs.

All the provisions for the old ladder bar setup on Adams Nova could be kept in place since it doesn't interfere with the Calvert suspension conversion.

Although Brian opted to run without it, Calvert Racing now offers a wheelie bar that is specifically designed to work with leaf springs. Because the way leaf springs are designed, traditional wheelie bars, like the setup you would use on a four link or ladder bar car, is completely different and won't be as effective. Calvert Racing recently designed wheelie bars that provide the correct geometry for a stock suspension car with a CalTracs, so for those wanting to not go sky high, these can help.

Over the years, Calvert Racing’s CalTrac bars and split mono-leafs have been the choice of champions in a variety of different drag racing classes, especially in PSCA and NHRA drag racing, so it made sense for Adams to convert his Nova to stock suspension using Calvert’s components.  The CalTrac bars work by improving your car’s instant center, by keeping the axle from rotating which, maintains pinion angle, and they eliminate wheel-hop. The second important piece to this conversion was the Calvert Split-Mono springs, which are made to work in conjunction with the CalTracs. The springs come with aluminum bushings in front eyes, and urethane bushings in the rear eyes. They are available in 200lb.—225lb. spring rates, as well as various ride height options. The leafs are also substantially lighter than multi-leaf springs for weight savings. Other components to this puzzle include Calvert’s beefy leaf spring perches, which are a lot tougher than the stock pieces that tend to bend when launched on hard.

Gary Rohe was able to make this mount off of the frame for the AFCO sliders out of steel tubing.

Once the eye provisions were made it came down to bolting on the CalTracs brackets and setting the center bar angle. Calvert recomends having the bar as level with the ground as possible.

The front spring eye provision also needed to made from scratch, but needed to be positioned the stock location.

We contacted Adams after this leaf spring conversion to see how it all came together. “Since I bought the car without a lot of the stock frame, I knew it would need some work to make it legal for the newer True Street rules,” Adams said. “Rohe was able to fabricate the mounts for the AFCO leaf spring sliders, and make the front eye mount in the stock location.” This allowed Adams to bolt up the leafs with no problems, and once the spring perches were welded on, it was only a matter of hanging the axle and bolting down the u-bolts. “It was pretty straight- forward, we just had to find where the leafs sit under a stock Nova and had to make the mounts for it. Everyone’s been going fast on leafs, so I thought I’d give it a try.” With the CalTracs and Split-Monos’s equipped, Adams’ Nova made it’s best 60 ft. time ever last year with a 1.29 and more recently went 5.65 to the eight mile with 1.32 60 ft. time, which puts his performances right around the 8.70 mark, so expect him be a top player in TREMEC True Street in 2012.

AFCO's leaf spring sliders are a popular upgrade for leaf spring cars. They allow the spring to function much smoother and provide more consistent launches that the flimsy factory shackle.

Calvert Racing also offers 9-way adjustable shocks that compliment the mono-leafs and Cal Tracs.

Anyone who has launched a leaf spring car hard for a long time knows how deformed the factory spring perches can become after only a few hard launches. Calvert offers stronger leaf perches that are a must for a high-powered drag car.

 

A 1.29 60 ft. time and a mid-five second pass in the 8th mile means Brian Adams Nova will be good for the 8-second zone in the quarter True Street this year. By converting to stock suspension, Adams is now also eligible for various drag radial classes as well. Check out this wicked x-body at an NMCA event in 2012.

AFCO
800.632.2320
afcoracing.com

Calvert Racing
661.728.9600
calvertracing.com

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