Mustang Restomod Guide : Suspension
Want to upgrade your vintage Mustang's suspension? In today's restomod market, you can go from mild to wild.
In the March '07 issue, we looked at some of the popular exterior modifications for Mustang restomods. Last month, we focused on drivetrain upgrades from stroker engines to overdrive transmissions. This month, suspension components have our attention. There are plenty of options vailable for upgrading a vintage Mustang's suspension. You can go mild with a traditional spring and shock package, or you can go wild with tubular arms and coilover shocks.
The Eyes Have It
For lowering the rear of your Mustang without lowering blocks or de-arching factory-spec springs, check into rear leaf springs with repositioned eyes, available from Mustangs Plus. A reverse-eye spring puts the mounting eye on the other side of the leaves to lower the car about 1-1/2-inches below the stock ride height. A mid-eye spring, which positions the eye at the end of the spring, drops the Mustang approximately 1 inch.
Rod & Custom Motorsports offers a pair of Mustang II-style tubular front A-arm suspension systems for '65-'70 Mustangs: one with standard shocks (RC-106) and the other with coilover shocks (RC-107). Both include a crossmember, motor mounts, spindles, 11-inch disc brakes, tubular upper and lower arms, and either manual or power rack-and-pinion steering. Because the factory shock towers are eliminated with the Rod & Custom kit, fender repair panels are also included. Six-way adjustable coilover shocks are included with kit RC-107 (pictured).
When Cinema Vehicles Services was instructed to modify several '67 Mustang fastbacks for high-speed action in the movie Gone in 60 Seconds, the company looked to Total Control Products for its adjustable coilover front-suspension kit. The kit includes TCP's tubular control arms and coilover shocks. It's significantly upgraded compared to the factory stamped-steel control arms and coil springs, yet it uses the stock mounting points for a simple installation.
The TCP upper and lower control arms are made from TIG-welded tubular steel to offer reduced deflection and improved ball-joint angles. Unique adjustment couplers allow precise setting of caster and camber. Because shims aren't used to align the frontend, the control-arm pivot shaft remains in full contact with the shock tower to further strengthen the suspension. Spherical ends, as opposed to the factory rubber bushings, eliminate unwanted deflection and movement at attaching points. Suspension geometry improvements include a lower center of gravity, higher roll center, reduced vehicle roll rate, quicker negative camber gain, and increased compression travel.
TCP's Vari-Shock coilover shocks provide adjustment for compression and rebound dampening. By rotating the spring seat ring, spring rate and ride height can be adjusted. Although the coilover springs are smaller than the factory's coil springs, they're more than strong enough to handle the weight of a Mustang.
To further take advantage of the coilover front suspension, TCP also offers a rack-and-pinion steering kit, precision adjustable strut rods, and forged spindles.
The original stamped-steel control arms on vintage Mustangs served their purpose in the '60s. Today, the Control Freak tubular arms from Blue Moon provide a huge step up from the original components. They offer additional strength, improved geometry, and more adjustability. Available from National Parts Depot, the control arms are made from 1.050x0.154-inch-wall seamless tubing, available in black powdercoat or a polished stainless steel finish. Also included is Grade 8 hardware for installation. Although not a coilover system, the Control Freak tubular A-arms are about as good as it gets without using more expensive coilovers.
RRS Struts Its Stuff
While most aftermarket suspension systems rely on a double A-arm-style configuration, RRS has taken a couple of steps beyond traditional. Instead of late-model or original-style spindles, RRS uses a custom spindle, designed using cutting-edge suspension theory and CAD com-puters to give vintage Mustangs improved handling characteristics with better tie-rod placement and superior camber shift (zero camber at full suspension droop and negative camber at full compression), as well as less unsprung weight over the axle. The spindle utilizes a sealed bearing assembly that never requires greasing and is replaceable at any parts house. The system maintains a stock wheel offset for correct vehicle tracking and allows stock or aftermarket lower control arms. The RRS hub requires post-'67 wheels with a 2.9-inch center opening.
With RRS's MacPherson strut assembly, owners can adjust ride height via the spring using the supplied wrenches without affecting camber due to the ample camber adjustment. Tailor-made for performance, the MacPherson strut maintains zero or near-zero to negative camber through its range of motion. The lack of camber changes make for more neutral steering characteristics and a meatier tire contact patch during hard cornering. The shock inserts are top-adjustable using the supplied screwdriver and are replaceable at most automotive retailers.
While the system is available without brakes, RRS offers a complete line of brake systems. Phase 1 (pictured) uses an 11.25-inch iron rotor and single-piston caliper. Phase 2 through Phase 4 systems come with a new type of rotor developed by Molycarbide, featuring NASCAR-tough technology and metallurgy. Phase 2 features an 11.7-inch Molycarbide rotor and dual-piston caliper with braided brake lines. Phase 3 also packs a dual-piston caliper but mounts a 13-inch rotor. Phase 4 has a Brembo four-piston caliper and a 13.6-inch thermal-stability Molycarbide rotor. Phases 1 and 2 can use 14-inch wheels, while Phases 3 and 4 need 16-inch wheels or larger.
The RRS strut kit works great with the company's rack-and-pinion, but it'll integrate with stock steering or other rack systems.
New from Heidt's Hot Rod Shop is the SuperRide II independent front suspension for '65-'70 Mustangs. A true coilover suspension for the ultimate in ride and handling, this kit comes with full front-frame boxing plates, tubular arms, dropped spindles, rack-and-pinion steering, 11-inch brakes, and coilover shocks with chrome springs. Available options include polished arms, larger brakes, black or red calipers, a power rack-and-pinion, a sway bar, and stainless tie-rod ends.
The Ron Morris Street Force tubular coilover front suspension from Mustangs Plus improves the handling and ride of vintage Mustangs by moving the lower mounting point of the coil spring and shock absorber to the lower control arm. By positioning the spring and shock closer to the wheel, less spring rate is needed to support the vehicle's weight, allowing the use of lighter-rate springs and shock settings for more suspension travel and improved ride quality. The Street Force suspension also offers improved geometry, adjustable ride height, and replacement ball joints. Available for '65-'66 and '67-'70 Mustangs, the system features QA1 shocks and simple bolt-in installation. A track version is also available.
The Upper Control-Arm Relocation Kit from Rancy Manufacturing is an affordable, do-it-yourself modification that improves cornering on '65-'70 Mustangs. The kit includes an aluminum template for positioning the new bolt holes, similar to the Shelby modification for '65-'66 GT350s. Also included are instructions and a pair of aluminum wedges to eliminate the bind created on the ball joints. Kits are available for 1-, 1-3/4-, and 2-inch drops.
Braced for Action
From the factory, '65-'70 Mustangs destined for the American market came with thin metal braces to connect the shock towers to the cowl area. When Carroll Shelby began looking for ways to strengthen the car's front end for his GT350s, he discovered that Ford installed a heavier-duty, one-piece brace on exported Mustangs. For Shelby, it was a quick-and-easy modification available over-the-counter at Ford parts departments.
The export brace, as it became known, is still a great modification for vintage Mustangs. Available from most Mustang parts vendors, the brace is a direct replacement for the production ones. The shock towers on most '65-'70 Mustangs have settled inward, meaning you may need to spread them to get the export brace to fit. In most cases, the car can be supported on jacks where the lower control arms connect to the shock towers. The resulting droop can spread the towers apart enough to install the brace. In extreme cases, a hydraulic ram may be needed to push the towers apart.
Although coilover suspensions are the rage these days, upgrading the factory suspension is a more viable and less expensive way to achieve improved handling for many vintage Mustang owners. The Grab-A-Trak suspension kit from Mustangs Plus is ideal for performance-oriented Mustangs that see frequent street use. Designed for a firmer-than-stock ride and flatter handling, the Grab-A-Trak kit includes 620-pound front coil springs; four-leaf, standard-eye leaf springs; a 1-inch front sway bar; a 3/4-inch rear sway bar; performance shocks; new leaf-spring shackles with rubber bushings; and polyurethane coil-spring insulators, sway-bar end links, and sway-bar frame bushings. Several upgrades to the standard kit are available, including mid- or reverse-eye leaf springs and a larger 1-1/8-inch front sway bar. With the standard Grab-A-Trak suspension, expect the rear end to sit at the stock height with a 1-inch drop at the front.
Due to front suspension design, every vintage Mustang has some degree of bumpsteer. It becomes more noticeable when the car is lowered or modified with suspension improvements that make the vehicle more responsive to steering input. When experienced, the car twitches or darts around on bumpy or undulating roads. It can also be twitchy during braking, pulling from one side to the other.
Bumpsteer can be eliminated by ensuring the tie-rod pivot point matches the travel of the spindle with a bumpsteer corrector kit from Pro-Motorsports Engineering. A spacer block, secured by a strap, "lowers" the tie rod so it's more in line with the lower control arm. With the angle of the tie rod and lower control arm almost identical, bumpsteer is essentially eliminated.
The Street Bandit kits from National Parts Depot contain all the ingredients for balanced handling at an affordable price. Available for '65-'66, '67-'70, '67-'70 big-block, and '71-'73 Mustangs, each component has been matched specifically to the vehicle for neutral balance and improved cornering without a stiff ride. The kits include a set of KYB Gas-A-Just shocks, a 1-inch front sway bar, a 3/4-inch rear sway bar, lowering coil springs, rear-end lowering blocks, and polyurethane sway-bar end-link bushings. NPD says maximum stability is obtained with new rear leaf springs, available separately.
No More Sway
Even with a fat sway bar up front, stiffer springs, and big tires, vintage Mustangs can use more help with handling. When roll control is out of control, add an adjustable rear sway bar from Scott Drake Mustang Parts. Measuring 3/4 inch in diameter, the Scott Drake bar (PN C5ZZ-5486-ADJ) provides adjustability for dialing in maximum handling. It's powdercoated to prevent corrosion and comes with polyurethane bushings. Scott Drake also offers a nonadjustable bar for '65-'66 and '67-'70 Mustangs.
They may be old-school, but the Traction Master underride traction bars from Tony Branda Mustang & Shelby Parts work as well today as they did 40 years ago. Vintage-Mustang leaf springs tend to twist or "wrap up" with hard acceleration, leading to wheelhop that can be violent enough to break axles and snap springs. The bars provide new attachment points for the rear axle, so it's not held in place solely by the leaf springs. Once installed, they also serve as trailing arms to solidly locate the axle in relation to the car. Installation is easy-the underride bars basically bolt-in with the exception of some welding that's required to attach the front mounting bracket. Look for PN TM1068 for '65-'66 Mustangs and PN TM1069 for '67-'73s.