First Gen Mustang Rear Suspension Upgrade With Total Control Products

Recently we upgraded our vintage ’65 Mustang fastback with a bolt-on front coilover conversion kit from Total Control Products (TCP), which updated the driving feel and handling of this classic. The best of both worlds in our opinion. We kept the originality by not having to cut up the front end of the car to install the kit, yet we changed to suspension components that were manufactured with modern technology. Because the conversion kit was a complete bolt-on system, it left the door open to revert to the original suspension if we ever wanted to return the car to stock.

The stock leaf-spring rearend offered a soft and mushy ride – too soft for our taste. We contacted TCP and found out that you don’t have to accept a mushy ride with a leaf-spring rear suspension.

Once the front suspension bolt-on conversion was complete, we took a hard look at the rear of the beast. It was obvious that we needed to match the front end upgrade with some modern components for the rear if we ever wanted to have a car that was balanced and behaved on the street. Once again we turned to Total Control Products for help. TCP’s leaf-spring suspension made the perfect rear suspension companion for our complete suspension overhaul.

About Total Control Products

Total Control Products (TCP) is one of the Chris Alston Chassisworks Brands along with VarishockChassisworks and KP Components. TCP offers system packages that are designed to work together as a complete bolt-on solution for front and rear suspensions, steering systems and chassis stiffening systems. To expand upon their various system packages, TCP offers multiple upgrades and options to custom-tailor the performance level of each kit. Practically any handling application can be accommodated.

Stock first generation Mustangs used very soft springs by today’s standards. – Lino Chestang

The TCP Rear End Suspension

There are many options when it comes to first generation Mustang rear suspensions; many of them are serious upgrades from the original leaf-spring style suspension. TCP’s g-Bar system is one of those rear suspension upgrades that gives you great ride height adjustments and several options for the anti-roll bar, along with a variety of spring rates. It’s hard to beat a system like that, yet we wanted to keep things on par with our front suspension upgrade.

You can make your life easier by applying penetrating fluid to all of the old hardware and letting it soak in for a half hour before attempting to disassemble the parts.

We wanted a rear suspension system that was a performance upgrade for a street vehicle without having to make any permanent changes to our chassis. A system that would add major performance but one that could be removed if we ever wanted to make a concours original car out of this project. We found the perfect combination of rear suspension components at TCP that would not only upgrade the rear suspension but would compliment the recent front suspension upgrade. Plus, we wanted a degree of adjustability and tune-ability in the suspension.

TCP’s leaf-spring suspension may loosely resemble the OEM leaf-spring system but that is where the similarities end. Total Control’s leaf-spring suspension system includes everything that you need to update your Mustang’s rear suspension with a modern system that provides more responsive handling. System options include 4, 4 1/2 or 5- leaf springs, with standard, mid or reverse mounting-eye styles.

Do You Need A Rear Anti-Roll Bar?

In an effort to correct excessive body roll on early muscle cars, the common approach is to add a large front anti-roll bar. This may initially appear to correct the issue, but with the unintended result of increased understeer on an already nose-heavy vehicle. To regain vehicle cornering balance a rear anti-roll bar may be needed. For mild street performance vehicles a rear anti-roll bar will provide a noticeable improvement to the “tightness” of the handling. 

If it is a specific look you are after then that’s a good enough reason to put one on your car. Nothing is better looking than TCP’s billet g-Bar, with splined-end anti-roll bar with billet aluminum arms.

What the Options Mean

Not only are the TCP leaf-springs manufactured with top quality alloy steel but they are available in two modified-eye styles, three separate spring configurations and three levels of  ride quality and performance.

“Different eye styles are used to alter ride height,” explained Total Control Product’s Lino Chestang. “Standard-eye being the stock height position. The mid-eye provides about a one-inch drop and the reverse-eye will sit roughly one-and-a-half inches below stock. TCP customers are making performance improvements to their cars, so we only offer mid-eye and reverse-eye springs.”

Choosing the ride height for the rear leaf-springs affects other areas of the chassis and should be considered when picking springs. “Selecting which eye style really depends upon how much the front suspension has been lowered and the desired stance,” Chestang cautioned. “Relative height change will vary depending upon vehicle weight and condition and style of the previously installed springs.”

When it comes to controlling spring rates, TCP uses different spring configurations. “Multiple spring rates are available by changing the leaf configuration,” explained Chestang. “Stock first generation Mustangs used very soft springs by today’s standards, ranging from below 100 lb/in to around 140 lb/in.” The goal is to achieve a more modern ride quality, with improved handling characteristics and TCP does that with increased spring rates.

There are a lot of differences between the stock OEM leaf-spring (on the bottom) and TCP’s performance leaf-spring (on the top).

Chestang broke it down into simple terms, “We offer a three spring stack for a stock-like ride, a 4-leaf with 165 lb/in rate for a firmer than stock ride but still very comfortable, a 4-1/2-leaf with 180 lb/in rate popular with pro-touring style builds, and a 5-leaf stack with 200 lb/in rate recommended for high-performance or heavy-load uses.” When it comes down to choosing a leaf-spring, the front-end ride height, desired stance and performance goals should all be taken into consideration.

When compared side-by-side, the extra leaf in the spring bundle and the location of the mounting eye are easy to spot.

Much like the TCP front suspension that we added to this Mustang, TCP’s leaf-spring suspension has different shock options available.  “We offer three shock options for this package,” said TCP’s Lino Chestang. “We have a factory-valved, single adjustable or double-adjustable shock options depending on the application or the buyer’s preference.”

Like the front suspension upgrade, we selected Varishock QuickSet 2 double-adjustable shocks for the rear.

When choosing between the single and double-adjustment shocks, Chestang reminded us of the differences. “A single-adjustable model with 16 settings for overall shock stiffness. And a double-adjustable model with dual 16-position knobs for independent adjustment of bump and rebound. The added adjustment range allows finer control of ride quality and greater flexibility when tuning for performance applications,” he clarified.

What We Installed

TCP’s leaf-spring suspension system (part #TCP RLSS-MU) includes the leaf springs (part #TCP LSM-M45), VariShock bolt-in shocks (part#14244-715), Spring plates, U-bolt set (part #TCP LSP-03), front bushing set (part #TCP LSP-04) and rear shackle set (part #TCP LSP-05) for 1964-1973 Mustangs.

In addition to the VariShock Quick Set 2 double-adjustable shocks, we went all out with TCP’s full leaf-spring kit and anti-roll bar.

We selected the mid-eye leaf-springs with the 4 1/2 leaf configuration. This would give us the one-inch drop in the rear that would align with the one-inch drop that we gave to the front suspension. Balancing the front and rear suspension is the key so we also selected the VariShock 14244-715 QuickSet 2 double-adjustable shocks to match the front end shock set.

The front bushing, U-bolt kit and rear shackle kits complete the full package.

Installation instructions for the leaf springs can be found in the bushing set and rear shackle set instructions. The U-bolt kit and leaf-spring plate instruction can be viewed here.


TCP engineers have worked hard to develop the right combination of materials and components to match the performance level for each application. In this case, we were looking for a good mannered first gen Mustang that could find performance happiness on the local streets. For that, the TCP engineers developed a package that used polyurethane bushings at each spring eye and chassis mount. “Urethane is significantly more durable than rubber and more difficult to compress, which reduces deflection and improves handling while still dampening noise and vibration,” said Chestang. “For something as simple as a spring shackle we actually spent a bit of energy making sure everything was correct before moving on to manufacturing. Correct meaning bolt holes and sleeves are precisely sized to correctly load the urethane for reliability and the best performance. That’s just the way we do things.”

TCP's manufacturing process includes selecting the right materials and manufacturing process so that everything is reliable and performs well. This means that everything is precisely sized.

 When it came to something as common as rearend U-bolt sets, we wanted to know what the difference was between the TCP set and a common set that we could pick up at the local parts store. “The original U-bolts, and standard direct replacement versions modeled after them, were made with 7-1/4-inch wide tires and 1960’s tire compounds in mind,” explained Chestang.

The Mustang designers never anticipated larger tires and softer tire compounds when the first gen Mustangs were built. TCP’s U-bolt kit is made with super sturdy components that far exceed the stock OE parts which allow for modern tire technology and trends.

“Today you find tires close to 12-inch wide under stock fender Mustangs with much better rubber or in some cases drag radial compounds. To meet the new levels of performance we custom make our own U-bolts. Bolts are made from alloy steel with an increase diameter of ½-inch, compared to the original 7/16-inch. Hardened washers and Grade 8 locknuts complete the hardware, making ours the strongest U-bolt set available,” he added.

Adjustable Anti-Roll Bar

We also selected TCP’s adjustable anti-roll bar (part #TCP ARRM1-12) for our street worthy Mustang. TCP’s anti-roll bar is specifically designed for leaf-spring style rear suspensions. Mounting directly under the rearend’s axle tubes with bolt-on clamps, this anti-roll bar setup offers plenty of clearance for the exhaust system. The anti-roll bar is a 3/4-inch solid bar that features multiple end link mounting holes that allow for rate adjustments. Like many of TCP’s other suspension components, the anti-roll bar is finished in silver with black-vein powder coating and comes complete with all hardware needed to install the system. Installation instructions for TCP’s adjustable anti-roll bar can be viewed here.

An anti-roll bar is recommended with the leaf-spring suspension. TCP’s anti-roll bar is designed to allow plenty of room for the exhaust system.

Road Tested

Now that the front suspension had been upgraded with the TCP bolt-on coilover conversion, and the rear leaf-spring had been beefed-up with TCP’s leaf-spring suspension, we could take the car to the alignment shop then out for a quick road test. “It was a lot stiffer than the worn-out stock suspension,” said Mike Magda, owner of the vehicle. “I’ll need some time to dial in the suspension to my comfort-level. The system has no shortage of adjustments of the VariShocks and multiple adjustable links,” he added. With a few laps around the block, we are sure that Mike will get the Mustang tuned to his driving style.

After we had installed the front and rear suspension upgrades, the Mustang was taken to an alignment shop and dialed-in. As we expected, the Mustang had a stiffer but comfortable ride quality. We want to play with some of the adjustments and try a little more aggressive street driving to fully evaluate the upgrade. Who knows… we may want to bump it up another notch before we are done.

Final Words

We found the front and rear suspension upgrade kits are a great value for the performance that you get. These kits are easy to install, easy to adjust and keep the chassis clean without any major modifications. You would be crazy to want to go back to an archaic suspension system, but you could if you wanted because these kits are bolt-in systems.

Chestang is obviously proud of the systems and when it comes to the leaf-spring upgrade, he states matter-of-factly, “This is a nice, complete Mustang leaf spring package. As we do throughout our product line, various options are offered within the package to custom configure the kit to best match the performance goal. The shock, spring rate, and ride height options of this system allow it to be setup for anything from a daily driver to a completely capable vintage race car.” We have to agree with him.

About the author

Bobby Kimbrough

Bobby grew up in the heart of Illinois, becoming an avid dirt track race fan which has developed into a life long passion. Taking a break from the Midwest dirt tracks to fight evil doers in the world, he completed a full 21 year career in the Marine Corps.
Read My Articles

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