Tech | Suspension Upgrade
As we go through our classic Ford cars, making them better, one of the departments many of us are concerned with is suspension. While the stock underpinnings are adequate for most things when in good repair, there is definitely a lot of room for improvement. A modern wheel and tire selection can make a huge difference in how your vehicle rides and handles, but for further improvement we often delve into suspension modifications. Even if left in a completely stock configuration, there is a lot that can be done to enhance the handling prowess of your classic Mustang or other special interest Ford. Many suspension companies now offer improved stock components that have additions like boxed control arms for increased rigidity or easily replaceable ball joints. Other stock component improvements include the replacement of rubber bushings with urethane units, while others might include heavy-duty versions of a stock part, such as antisway bars. Certainly the replacement of OE shock absorbers with more modern units such as those made by KYB, QA1, Koni, or others will offer improved suspension control.
If you're dealing with a 45-year-old...
If you're dealing with a 45-year-old car, sometimes the best and most economical way to go is to get your car back to new OE standards. If your car has shot ball joints and sagging springs, then you'd be surprised how much difference a new stock-style suspension can make. This Grab-A-Track hardware from Mustangs Plus is a great value, and installing it along with a correct alignment will do wonders to refresh the handling of a tired car. Opentracker Racing, Cobra Automotive, and National Parts Depot are also good sources for stock configuration suspension components.
When we decide to go beyond the parameters of the stock configuration, there are now so many choices that it can be bewildering which direction to choose. Much of your choice should be dictated by what you like to do with your car. Certainly a drag racing fan will have different requirements than someone who is interested in road racing. For example, while many drag racing fans will install 90/10 shocks and remove the front antisway bar to improve weight transfer, these modifications would be the last thing a road racer would want to do (and can be fairly dangerous to drive on the street).
For flat cornering, a larger-than-stock front antisway bar and shocks that control the wheel in both directions (both jounce and rebound) would be much more useful. Still others who are interested in more power in the form of a different engine would go yet another route, allowing the fit of said engine.
The same reasoning holds true...
The same reasoning holds true for shock absorbers. Having your unsprung weight flying around undampened is one of the worst things you can have going on when it comes to vehicle handling. These Grab-A-Track shocks are a good replacement for worn OE units. If you'd like even more control over unsprung weight, then a gas shock or high-performance unit like a Koni can be a good way to go. Single- and double-adjustable shocks offer even further tuning adjustments for varying road/track conditions, vehicle weight, and more. Just remember, the harder the shock absorber and spring rate, the harder the vehicle ride will be; so you'll want to analyze your priorities before you decide on a selection. While Koni shocks are hard to beat on a road course you may not like them if your car is primarily street driven.
Many kits are now available to allow the removal of the original shock towers, thus enabling the installation of a larger-than-stock engine. In the creation of this article we talked to many different suspension manufacturers to get their takes on why these different selections work the way they do and the different advantages they offer. Let's take a look at some of the different suspension options out there and how they offer different advantages over other types of suspension, including the stock setup.
Align It In Time
Many of us will choose to do our suspension upgrade project in the home garage with a floor jack and a set of jackstands. Keep in mind that once a front suspension swap is completed, you're going to need an alignment, no matter how careful you've been to retain the old settings. Matter of fact, most aftermarket suspensions come with suggested alignment specs to make use of the better handling inherent in the new suspension's design. In addition, remember that the drive to the alignment shop should be a short one and be done right away. If that's not possible then make arrangements to trailer the car to an alignment shop. Even 25 miles on a set of tires with the front end out of whack can be enough to badly damage a set of new tires; not to mention it's unsafe to drive with such poor alignment settings.
While we're talking about...
While we're talking about handling and suspension upgrades that you can do with your car in the stock configuration, one of the best ideas is the addition of a larger front antisway bar. This photo shows two good choices, again from Mustangs Plus. At the bottom of the photo is a 1-inch diameter bar, which is a substantial upgrade from the small bar found as stock on early Mustangs. Antisway bars make a huge difference in the reduction of body roll and if you want rock solid control on the freeway cloverleaves, then the 1 1/4-inch bar shown at the top of the photo is a good high-performance choice.
Our experience has shown that...
Our experience has shown that a rear antisway bar can also be of great value in reducing body roll. This heavy-duty bar comes from National Parts Depot and installs onto the car with very little modification to the vehicle. After the addition of this bar, we were amazed, as body roll seemed almost completely eliminated even in the sharpest turns. Never run a rear bar without a front bar of the same size or larger, as this can cause snap oversteer or the lifting of the inside tire on turns.
Another key to good handling...
Another key to good handling is a low center of gravity, meaning a low roll center. Adjusting the ride height and rake on your car with a standard configuration suspension requires changing the physical spring for one of a different rating. Even with new springs you may find that your front end is too high. You can make final adjustments before alignment by trimming the free height of your coil springs, as shown here. We'd recommend cutting no more than 1/2 a coil at a time to make sure you don't go too far in your final lowering adjustments, just note that this can cause the spring to ride stiff and is generally not recommended for variable-rate springs-when in doubt order a different spring.
Likewise a simple addition...
Likewise a simple addition to your rear suspension can accomplish a nice lowering increment. While we wouldn't recommend lowering blocks for a radical lowering job, these 1-inch blocks don't require U-bolts too much longer than stock and a nice 1-inch drop can be accomplished out back with this kit fairly easily.
Simply remove the stock U-bolts...
Simply remove the stock U-bolts from the axle and install the block between the spring and axle. We painted our blocks black before the installation to keep their addition hidden from the eye once installed.
Another way to accomplish...
Another way to accomplish rear suspension lowering on a stock-type suspension is to use mid- or reverse-eye leaf springs. On a stock spring, the leaf rolls into the mounting eye at the bottom of the eye. On the mid-eye leaf springs (seen here) the leaf rolls into the mounting eye exactly in the middle of the eye, accomplishing a nice mild drop in the 1- to 2-inch range. For a more substantial drop you can choose reverse eye springs. On these components the leaf rolls into the eye at the top of the eye creating a more radical drop. Either of these two options allows for a drop in height without negatively affecting spring rates. Also seen here are much more robust-than-stock rear spring shackles. These serve to more positively locate the rear axle by eliminating lateral slop by using much stronger side plates and urethane bushings.
The next step up for a front...
The next step up for a front suspension upgrade while retaining the stock mounting points features boxed lower control arms for enhanced rigidity and control. Likewise, the upper control arms are also reinforced with gussets and extra welding. Performance shocks, lowering springs, larger diameter antisway bar, and high durometer bushings round out this typical bolt-on front suspension package.
A typical bolt-on rear suspension...
A typical bolt-on rear suspension setup you'd find in many Mustang catalogs includes mid-eye leaf springs, performance shocks, urethane bushings, as well as a Panhard rod assembly. The Panhard rod serves to locate the rear axle securely with respect to lateral movement and this works to further enhance vehicle control.
This photo shows the rear...
This photo shows the rear suspension and Panhard rod assembly in place on a '68 Mustang. No longer does the rear axle rely solely on the leaf springs for situation in the vehicle and the rod assembly gives the axle a solid connection to the frame that is inflexible and independent of the leaf springs.
The next step up for front...
The next step up for front suspension modifications dispenses with the stamped control arms altogether. The factory style stampings simply aren't as rigid as a fabricated tubular control arm, such as these examples offered by Global West. The kit shown here includes the template required to accomplish the same 1-inch upper control arm drop first used by Carroll Shelby on the '65 Shelby GT350.
Another famous maker of tubular...
Another famous maker of tubular control arms and advanced suspension is Total Control Products-a division of Chris Alston Chassisworks. It designed an adjustable coilover shock suspension system that is still a complete bolt-in with no major modifications. The equipment includes front strut rods where the rubber in their mounting to the car is completely eliminated. With this flexibility gone, alignment changes during suspension movement are minimized, further enhancing concise control.
Likewise, Total Control offers...
Likewise, Total Control offers an advanced rear suspension package. In this arrangement the axle is carried in a cradle that installs onto the back end of the car. The shock absorbers are laid over horizontally to conserve room and they provide their dampening action through an advanced and compact rocker arm system. In addition to the advanced shock absorption system, the setup also includes a long moment torque arm attaching to the axle at the differential and a Watt's linkage as well. The Watt's linkage serves the same purpose as a Panhard rod arrangement in limiting lateral movement of the rear axle. Some welding is involved in the setup of this rear suspension.