Steve Baur
Former Editor, Modified Mustangs & Fords
March 10, 2011

If you're just joining us, last month, we embarked on an adventure that will hopefully turn a racy red Mach 1 Mustang into the corner carver that it should be. Equipped with a 351 Cleveland and three-speed automatic transmission, our subject '72 Mach has the foundation for speed, as well as the looks. Last month, we overhauled the front suspension using Mustangs Plus' Super Starter kit, and this month, we finish up the rear suspension upgrades.

Mustangs Plus offers the Super Starter kit for all '65-'73 Mustangs. While each kit contains basically the same parts, Mustangs Plus custom tailors the selection to each vehicle and owner's needs. The Super Starter combines three subsystems into one big package that includes a spring and hand-ling package, a suspension rebuild package, and a steering upgrade package.

It's a great and inexpensive way to revive your old tired Mustang and equip it with new components from top to bottom. The revised spring rates and mounting options should tighten up handling dynamics, and lower the car about an inch for a lower center of gravity and a more modern and aerodynamic look. Prices start at $799.95 for the Super Starter kit, and Mustangs Plus backs every component with a lifetime guarantee.

To suspend the rearend of our '72 Mach 1, Mustangs Plus' Bill Faull set us up with a 41/2-leaf, mid-eye spring. The 4 1/2 represents the leaf count, with our set utilizing four full leaves and a half leaf on top of the main leaf.

"We put the half leaf on top of the main leaf to add strength to the leaf springs without adding a lot of stiffness to the ride," says Mustangs Plus General Manager Bill Faull.

"These are designed for the street-oriented driver who jumps on the gas now and then. These springs have a strategically placed extra leaf to minimize wrap up and help prevent wheelhop under load. They will set the rear of your Mustang 1 inch below stock ride height."

Over time, your Mustang's ride height can change if the leaf springs on the car have started to sag. If they are in full droop, the Mustang may be sitting 3-6 inches lower than normal. Depending on the look you are after, Mustangs Plus can accommodate most all enthusiasts.

"The standard-eye spring would put the rear back to stock ride height, while the mid-eye spring would put the rear 1 inch below stock ride height," notes Faull. "The reverse-eye spring would put the rear 1 1/2 inches below stock ride height. Most people match the leaf eyelet to the front coil spring that they are using, if they are relocating the upper control arms, and if they want a rake or not."

For those who are into the more technical details, Mustangs Plus offered the following information regarding the spring's rates for the Mustang rear leaves:

GT Leaf 165 lb/in
4 Leaf 165 lb/in
4 1/2 Leaf 175 lb/in
5 Leaf 195 lb/in
5 1/2 HD 300 lb/in
Add 500 lbs for load rating

Due to scheduling issues with our track venue being closed for the season, we had to postpone our follow up testing. We plan to have the full evaluation, along with some other modifications coming up in the June '11 issue. We're also looking at several performance mods to help unleash the hidden potential of this sleek Pony in the issues to come. In the meantime, dig into the captions and photos to see how easy it was to upgrade the rear suspension of this '72 Mach 1 Mustang.

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