Best Mopar Suspension Upgrades

Table of Contents

‍What Are Some Best Stock Suspension Upgrades?

If you don’t care about history but are just looking for a smooth ride, then go ahead and modify your suspension with airbags or coilovers. (If you want to make your Mopar a low-riding bump scraper, go ahead; we aren’t stopping you). But on the rare chance that you like restoring stuff the way it might have looked and driven when it first came off the factory line, read on.

Torsion Bars

The Torsion bar is a long metal rod anchored to the car's frame at one end and connected to the lower suspension components. Its purpose is to twist when the wheel encounters a bump in the road, helping the car absorb the shock and restoring it to its original position after the road hazard has passed. It acts as a guard to the other suspension systems so that they don’t have to take the brunt of the force of a pothole or bump and break.

While the torsion bar is relatively easy to replace, older classics tend to have the bars stuck in place pretty tightly, so care must be exercised when removing them. We recommend purchasing a torsion bar removal tool from Mancini Racing. It bolts to the torsion bar, and you beat on the extension with a hammer, but be careful not to damage it. Also, if you plan to reuse the torsion bars, mark them left and right because it matters, and mixing them up can cause a lot of trouble).

New torsion bars come in all kinds of diameter sizes and spring rates and are rated for different applications, from drag racing to street, so you need to know what kind you want before you order a pair. If you are working on a car with a slant six, you want a softer bar for daily driving. Heavy-duty suspensions like the 413 or 440 RB or a 426 Hemi will definitely need more oversized bars (diameter and length).

A good rule of thumb is to use a torsion bar one-tenth the weight of the front of the car. Check your factory specs to ensure that you buy the correct size. If you install a torsion bar that is too much for the vehicle, you can create ride issues, and chances are they may not fit. (Many restorers might argue for a coil-over system if you plan to stress the front end (racing), and we would agree, but if you just want to restore the car to its factory ride, or use it as a daily driver, stick with the torsion bars).

Pros

Upgrading torsion bars can improve car ride
Easy to adjust and maintain
Stock equipment

Cons

Sometimes, it is tough to remove

Leaf Springs And Hangers

The rear suspension of Mopar is the stuff of legend, and many classic muscle cars are still running fine with the front and rear leaf springs intact. Mopar used more robust leaf springs in their cars than competitor’s coil springs to handle the stresses that might be inflicted on the rear axle due to imperfections of the road and the weight of the chassis.

Unlike coil springs that center the force in one area (spring), a leaf spring spreads the stress and helps absorb the force. (Smaller leaf springs were in the front, which made Mopar's nose heavy).

There are different kinds of leaf springs, such as mono leaf springs, which consist of a single bar (thicker in the middle and thinner toward the ends). Then there are multi-leaf springs, which are several layers of metal of varying lengths, all placed on top of each other. The force the rear end has as it drives is absorbed and spread out by the friction between the plates as they rub against each other. Multileaf springs are usually used in heavier vehicles, so you need to check to see which type your car has.

Mopar makes leaf springs for different applications, such as street, racing, or competition. If you plan on upgrading the leaf springs on your daily driver, stick with the basic stuff, swapping out the stock springs for replacements. Different leaf springs often have different spring rates depending on how stiff you want the ride. (Because there are many different configurations, be sure to talk with your vendor and ensure they are up to speed on the exact specs of the car and the kind of ride you are looking for). The folks at QA-1 or Mancini Racing can help you sort everything out, along with hangers that you will likely want to replace in addition to the leaf springs.

Pros

Upgrading rather than replacing leaf springs can provide better ride quality
Perfect for daily drivers
Easy to install

Cons

Not adjustable

Upper and Lower Control Arms

A control arm is a hinged link that connects the car’s frame to the wheel hub, allowing the tire to move up and down as it rides over a bump so that the tire can maintain complete contact with the road. There are upper and lower control arms, often known as “A” arms (due to their vague shape of the letter A). (The upper control arm attaches to the top of the wheel assembly, and the lower ones to the bottom). These arms help handle bumps in the road and keep the tire vertical as you steer and maneuver.

In older model cars like classic Mopar muscle cars, the upper control arms are connected to the steering knuckle using an upper ball joint. (The lower arms are connected by rubberized pivot points called control arm bushings. Replacing control arms doesn’t always mean new ball joints, but it doesn’t hurt to replace them while you’ve got everything disassembled.

There are lots of basic OE control arms on the market that are fine to use in typical daily driving situations. Still, consider replacing the stock units with adjustable tubular control arms. These adjustable arms allow you to dial in the camber and caster to push larger tires. We like the flexibility to reset the factory specifications or to adjust the angles should we need to do so. (SPC Performance has some excellent adjustable control arms should you wish to get them for your classic Mopar).

Pros

Upgrading can provide increased durability for front suspension system
Improved ride quality

Cons

None

Sway Bars

Anti-sway bars are essential for Mopar muscle cars that like to go fast around corners. The anti-sway bars resist the roll when a car moves quickly around a turn. (If you have ever experienced a lift on one side of the car during a high-speed maneuver, you have encountered a roll. The sway bar helps keep all four tires on the road.

Since Mopar did not use anti-sway bars on all models, you must determine if your classic car has them (front and rear, front only, or none). Should your car not have them installed (they were offered as options on some models), don’t fret. Many aftermarket companies have produced anti-sway bars with brackets, which can be fitted to cars that might not have initially had them installed.

For classic Mopars, it is not unusual for there to be no rear anti-sway bar. Since these components (especially front torsion bars) are designed to help with cornering under speed, you must determine just how much anti-roll you need. If you are driving a daily driver like my grandfather did (as gently as possible), you might not need to upgrade. If you are planning on testing the car for speed and want more confidence for it as a “corner carver,” then by all means, upgrade.

It is essential to determine the roll couple distribution (the relationship between the front sway bar torsion and the rear torsion). Once again, you should be careful about the kind and size of the sway bar you install. Since an anti-sway bar is a torsion bar and can significantly affect the vehicle's handling, you can get too much weight toward the front or the rear and create steering issues. (Many restorers need to put a lighter bar on the rear, which creates serious oversteer). Remember, the thicker the bar, the stiffer the ride. For a typical Mopar muscle car, you need to have the bulk of the roll coupled to the front so that the Mopar is nose-heavy and the front suspension handles most of the resistance load.

Another decision you will need to make is whether you want to install a solid bar or a hollowed tubular one. Many aftermarket companies are making tubular anti-sway bars that are just as strong as the original Mopar bars but are also lighter in weight. (This means that installing them helps our old Mopar go faster. We like the front and rear tubes that Hotchkis makes).

Pros

Can help with cornering
Reduces roll
Easy to install

Cons

It can be expensive depending on the type
Not all Mopar cars use them

Shock Absorbers

Shock Absorbers are essential to a front suspension upgrade because they dampen and rebound the springs and suspension of the car. (Your car experiences constant vibrations as it travels). While replacing stuff under your Mopar, you might consider upgrading your shocks. All kinds of shock absorbers are available, from cheap ones that don’t last very long to the expensive mono-tube variety that can cost you more than your monthly mortgage payment. Safe to say, there are lots of different kinds for all kinds of budgets, so it just depends on how much you want to spend.

Shock absorbers are oil-filled cylinders that move up and down in response to your vehicle's suspension. The kinetic energy that your front springs encounter is transferred to thermal energy inside the shock, where the movement of a piston forces tiny droplets of oil through orifices in the piston head. The oil acts both as a lubricant and a decelerant, slowing the suspension and dampening the rebound.

If you decide to get a pair of shocks for your classic, we like the self-adjusting Blisteins that Performance Online offers (they are reasonably priced as well).