We’re being pretty diligent about keeping our perennial project ’69 Dodge Charger R/T “Killer Kong” under budget. Right now, in its current form, we’ve got just shy of $10,000 in the almost ready-to-drive Mopar. That includes buying the car outright, getting the car’s rippled panels straightened out and painted, and getting it back to road worthiness. So, when it comes to our finances, we’re pretty judicious about what parts are “must haves” versus what are “would like to haves.”
For the longest time, good ol’ ‘Kong rode on pretty stock suspension. Our tie rods, idler arm, end links and ball joints are pretty worn out and in need of replacement; we’ll get to those soon enough. Kicking around, we landed a pair of factory Ma’ Mopar Super Stock leaf springs (five- and six-leaves). We actually scored a quartet of original, unopened Mopar Performance steel tube gas shocks at a swap meet ages ago and smirked at the idea of putting on a set of brand-new 30-year-old shocks.
Unfortunately, as the yellowed cardboard box read, these were just replacements – not the kind of shocks we’d need to get our big B-Body to hook up, and since we were looking at getting this copper Charger down the 1320 well below the 11-second mark, regular old gas shocks just weren’t going to cut it. Just like tires and springs, shocks can make an incredible difference in a car’s ability to hook up and launch. Many opt for the Band Aid package of 90/10 single-adjustables up front and a pair of 50/50 gas shocks out back. While these will offer a big improvement over the stock dampeners, getting our ride to hook right wouldn’t be fixed with a “one size fits all” approach.
Finding The Right Fit
The right combination will make for a reliable setup at the track, which of course, results in great times. You can replace the tires, tinker with the tire pressure, or even mix up at what RPM you launch at, but neglecting the shocks is like leaving out a key ingredient of a favorite recipe. The result will never be right.
High performance shocks notably improve the overall responsiveness of the chassis. The classic Mopars were unibodies, meaning they incorporated the frame into the body, rather than resting a body on a frame like so many GM muscle cars. While notably lighter, unibody cars are prone to flex when under heavy duress.
Understanding that, we went about reinforcing our Charger’s fractured framework by installing a set of torque boxes and sub-frame connectors. These will drastically reduce our B-Body’s torsional flex and permit the suspension to work more effectively.
Removing the variable of body flex, we were able to focus our attention to assembling an tunable suspension package. What this meant was digging into our budget and going with a precision double-adjustable shock. Since all a shock does is dampens (resists) chassis movement by pressing oil through valved passages, an adjustable shock simply manipulates the fluid movement through the valving, changing the shock’s softness and stiffness at will, allowing us to find the optimal chassis setting.
Playing As Singles Or Doubles
That’s why we went to QA1. QA1’s massive selection of performance shocks and struts, be it non-adjustable, single-adjustable, double-adjustable and “R” series drag racing, ensured that we’d find the right package for our ’69 Dodge Charger. While QA1’s non-adjustable shocks are great options for “comfortable, consistent ride,” we knew our Mopar was destined for the track, so we eyed their adjustable shocks first and foremost.
Now there are two kinds of adjustable shocks; a single-adjustable and a double. Singles typically only allow adjustments in only one direction, the “rebound” or the shock’s resistance to extending. The compression rate (bump) valving is preset by the manufacturer, and while “velocity sensitive,” it will respond to the differences between a 12-second street car and a 9-second door slammer. A double-adjustable shock, on the other hand, allows calibration of both the bump and rebound separately.
QA1’s Dave Kass put it this way, “The biggest reason that people turn to adjustable shocks is that there are so many different applications out there. It is impossible for a non-adjustable shock to be perfect for each and every person. A single-adjustable shock is a great way fine tune the ride quality and overall performance of the shock absorber. This allows the customer to make small changes to make the vehicle perform the way they want it to perform. Generally the single-adjustable shocks are good for street and casual racing.”
Kass continued, “If you are more performance oriented and need more adjustability, the double adjustable is your answer. This shock will allow for independent adjustment for compression and rebound. Whether you have a dedicated race car, or a street/strip machine these shocks will give the performance edge needed. The adjustment range is so vast it will allow you to drag race in the morning, autocross in the afternoon with the valving of a race shock and then drive your wife to dinner in the evening with the softer more comfortable valving you expect from a street shock.”
What All The Hubbub Is About
What the double-adjustable shock offers over the non- and single-adjustable is its superior tuning. If the rest of the car’s suspension is dialed in, the shocks can perform in a myriad of ways, be it softening up the rebound setting to plant the tires faster and with more force, or stiffening the bump setting to hold the tires down longer, staving off wheel slippage, tire shake or wheel hop.
During chassis separation, the point where the suspension is extended, pushing the axle housing away from the chassis and when the tires are pressed downward, vector forces push the chassis up and forward while the opposite is happening to the rear axle. It is here when the tires are compressed and the sidewalls start to “wad up.” So, as the car begins to move forward and the tires begin to bite, torsional force exaggerates this separation, often causing wheel hop, which occurs as the tires try to return to their original, unwrinkled shape. By firming up the rebound setting, this excessive chassis separation can be controlled and your tires planted.
As a rule of thumb, compression is a key setting to a properly tuned suspension, particularly as it determines how long to press the tires down during and after chassis separation. When a shock is set with a softer rebound, a slightly stiffer compression setting aides to control the rebound of the tire.
Of course, track testing is really the only true barometer to proper chassis tuning, especially with each individual setup. We’re still a little ways away from getting ‘Kong out on the track, but we’ll make sure to break down our tuning process.
Upon installation, many suggest mounting your shocks upside down. This is not because the shock magically works better on its head, but rather, to reduce the “unsprung weight,” or anything that would hang from your car if it was lifted up on a four-post lift; mainly the wheels, axle housing, struts, shocks, brakes, and to a lesser degree, your shocks.
Reducing unsprung weight decreases the chance of wheel hop or tire shake, as the less mass moving around will give the shock a better chance to control the axle housing during separation, allowing a softer shock setting and ultimately, quicker runs.
By flipping them upside down, the heavier end of the shock would be mounted to the body instead of the suspension. This was a factor for steel tube shocks, but so much with QA1’s aluminum Stocker Star shocks. Made from aircraft-grade aluminum, these lightweight double-adjustable dampeners feature twin anodized black knobs that permit up to 324 valving options.
And while we couldn’t imagine needing it, all of QA1’s shocks are completely rebuildable. Simply send the shocks back in to QA1, and their trained technicians will put your struts back to as-new condition, providing an added assurance that QA1 stands behind their product.
With basic hand tools, our install took us a couple of hours. And since you don’t have to stop to take pictures for an article along the way, we’re sure it’ll take you less time to drastically improve your classic’s ride and tunability. Once we get ‘Kong to the track, we’ll walk you through tuning its suspension. Stay tuned!