Last month we set out to infuse some modern road manners and corner-carving ability into an unlikely candidate, a ’71 Chevelle wagon. Why a wagon? Well, our theory is that if a pile of parts can make a big tank handle and ride great, then the benefit to the more common two-door coupe should be even better. Besides, there’s something super cool about dropping jaws by flinging a family trickster through cones.
In Part One we stuffed a bunch of components from Global West under the nose of the Chevelle, including a close ratio steering box and gigantic Wilwood binders. This time we’re giving equal attention to the back half of our A-body and then we hit the track to see if all the welding, wrenching, and cash paid off.
After supporting the back of the Chevelle, the first thing we did was remove the tired factory shocks; this gave us access to the upper spring pocket. One of Global West’s main design considerations was to keep the load from the spring in the original location on the frame.
Global West included a template to help make a 3-inch hole in the proper spot for the rear coilovers.
With the hole made Global West’s Eric Norrdin, welded in the new upper shock mount plate. This gave us a rock-solid place to mount the rear Penske single-adjustable coilover shock.
The wagon was already running a sweet Currie 9-inch hybrid rear that incorporated GM ends, but with the larger Ford bearings and axle retention system. Wilwood offered a rear disc system perfect for this and the first step was to install the new parking brake assembly. We also cut away the stock-style shock mounting bracket since it won’t be used with the new coilover system.
The W4A rear calipers may share the same external look of their six-piston cousins up front, but that’s just for aesthetics. Wilwood has engineered them to have the proper piston area to complement the fronts. They also feature a bridge-bolt design for easy pad swaps. Speaking of pads we’re running BP-10 pieces, which provide a good balance between stopping grip and street manners.
The giant four-piston calipers and equally massive 14-inch (1.1-inch wide) rotors easily fit inside our 19-inch Evod wheels. Like the front rotors Norrdin had to assemble them to the hat and safety wire the fasteners. You can also see that the factory shock-mounting bracket is now just a fond memory.
The first step in setting up the rear suspension and coilover mounts was to install these two Global West brackets. They are indexed off the existing upper bolt and the added lower bolt gives another point for the lower control arm to be bolted to (on low ride height cars). To make sure the pinion angle doesn’t change, the upper control arms were left in place and the lower arm was swung into position to make sure the boltholes were in the correct location. Once confirmed the brackets were then tack welded.
Once tacked in place Norrdin could fully weld the brackets together. We then used a small spacer to simulate the bottom end of the shock and attached the antisquat bracket. Its position on the axletube is determined by swinging it upward until it contacts the axletube. It’s a slick method that pretty much guaranteed that everything would end up in the right spot.
Next, this bracket was welded onto the axletube. A small gusseting plate was also welded to the bottom of the bracket to give it even more strength. There are now two positions to mount the lower control arms. This allows fine-tuning the suspension’s antisquat, which is especially helpful in drag racing since wheelhop is a real bummer.
Here’s a view of the completed driver-side rear suspension. Notice that the Penske shock and Eibach spring combination is perpendicular to the ground. As Norrdin explained, “We put the coilover shocks straight up and down so the springs require no correction factor. When they are laid over at an angle, you have to calculate a correction factor for the spring rate. For example, a shock mounted straight up and down on a car has a spring rate of 200 pounds. But if that shock combo is mounted at a 25-degree angle then the spring rate would have to be increased to 243 pounds (0.82 correction factor) for similar suspension performance. The angle will also affect the shock adjustments, and fine-tuning the suspension is easier when the shocks are mounted straight up and down.”
On some applications Global West doesn’t run a rear sway bar, but due to the wagon’s long rear overhang and high center of gravity, they thought it would help control any excessive roll. The coilover bracket acts as a mounting point for the 0.75-inch rear sway bar while the endlinks are attached to small brackets welded to the frame. When finding the proper location for these brackets the suspension needed to be under load and close to the desired ride height. At that point we simply made sure they were perpendicular to the ground. With that done we only had to bleed the huge Wilwood binders and toss in a “performance street” alignment.
Putting it all to the test
Sure, the new parts look great, but what we wanted to know is how much better the ’71 would perform. The first step was to take the Chevelle out to our test venue in El Toro, California, for some quality cone-dodging time. We then brought it back out with all it upgrades and ran the same tests. To clear the new Wilwood brakes we hit up Shaun Dove at EVOD Industries for a set of his retro-styled billet rollers in 18x9 front and 19x10 rear. For rubber we chose 300 treadwear BFGoodrich KDW tires from Driverz in 275/35-18 front and 295/30-19 rear. This tire offers a great balance between high grip and excellent wear. We should also note that the wagon drove great on the highway and streets. The wallowy feeling was gone as was the vague steering. The ride was firmer, but in a good way, and the suspension still managed to absorb bumps and dips with ease.
The ’71 looked like it was getting ready to flip over onto its roof. It was fun to watch, but not conducive to good handling. Before getting motion sickness our wheelman Nick Licata was able to nail down a best time in our 420-foot slalom of 7.26 seconds. This equates to 39.6 mph and is pretty abysmal in the grand scheme of things. For a disc/drum combination the brakes weren’t as bad as we thought and the 60-0 mph braking distance was 154 feet. Good for a 40-year-old car, but not even close to what a new car can put down.
With the wagon revitalized we headed back to our El Toro test track. After a few warm-up laps we were rewarded with a best slalom time of 6.24 seconds or 46.3 mph. This was a huge improvement over the previous tests, especially considering the Chevelle was set in cruiser mode and not in “kill” autocross mode. Moreover the wagon’s crazy body roll was now under control and the tighter steering made the Chevy easier to weave through the cones. In the braking test we saw an even more impressive improvement with a 126-foot 60-0 stopping distance. Knocking over 28 feet off the distance is huge, and, best of all, this performance was repeatable while the stock brakes were mush after only two or three hard hits.
The wagon also gained big time in the looks department. The lower stance and killer EVOD wheels is a far cry from the 4x4 look the Chevelle originally sported.