Operation EFI: Tracking True

When I began the restoration of the car that became the Operation EFI project car, I wanted something that carved the corners a little sharper than a 40 year old grocery cart. Advances in suspension geometry, steering components, and braking tech in the past four decades made it a no-brainer. Getting a few parts that wouldn't break the bank would be worth it in the long run, and might even help me take the bends alongside cars that only had half an engine.

I started at the ground and worked my way up. I sold off the stock steel wheels in favor of often-tried-but-still-true Cragar S/S's. With 15" x 7" up front ant 15"x8" out back to help put the power down, a set of new wheels was going to be necessary for what was coming next.

With a 302 cubic inch power plant up front making twice the power of the squirrel that originally lived under the hood, the Mustang was going to need a little convincing to come to a halt and the factory drums were all removed in favor of something a little more persuasive. Utilizing disc brake spindles from a 1975 Ford Granada, a set of Wilwood rear discs on  the Ford 9" rear differential and a Wilwood master cylinder and proportioning valve, the new binders would drag the car to a halt in short order.While not top-of-the-line, the new braking system would make the old drum brakes look and feel like a rusty, cylindrical, forty-year-old mass of pudding.

The modern disc brake is an elegant solution to an age old problem - dissipating kinetic energy before you crash into something.

With longitudinal acceleration taken care of, it was time to teach the Mustang to barrel-race. Polyurethane bushings were used throughout the suspension to reduce compliance and promote crisp feedback. Subframe connectors were added to keep the chassis from folding like a wet blanket as I powered out of a hairpin, and the upper control arms were relocated using a Negative Wedge kit from Dr. Gas.

By dropping the upper control arm (UCA) mounting points 1.75", the Dr. Gas kit vastly improved the camber gain of the stock suspension. As a car enters a corner, the body has a tendency to roll or tip to the outside of a corner. This has the effect of compressing the suspension, which affects the angle from the vertical the tire makes with the road, known as camber. By changing the relationship between the body angle and angle of the tire, the tire-road contact can be improved, keeping you on the road and out of the fence the neighbors have already replaced three times this year. 'Negative Wedge' describes the components in the kit that allow the stock parts to function at this new location. By placing the wedge under the upper balljoint, the angle and the subsequent stress is reduced.

A similar modification is known as the 'Shelby drop.' Pioneered by Carrol Shelby with the Shelby Mustangs back in the '60s, the drop refers to lowering the UCA mounting points by 1", which is enough to improve camber gain but not so much as to stress the ball joints unduly. There are always other parameters affected by these modifications, and the most common side effect of this modification is bump-steer, or changes in toe (the direction the tire points as viewed from above) caused by suspension travel. This effect is exacerbated by the Granada spindle swap, but is correctable via a tie-rod modification kit. I chose to forgo this extra step for now.

With the suspension tweaked, it was time to do something about the steering. Created in a time when rack-and-pinion steering was the exception, not the rule, the factory recirculating-ball and worm-gear box suffered from excessive free play, a lazy steering ratio, and in the event your car had power steering, massively overassisted steering input. I wanted the car to be as lightweight and nimble as possible for a car with almost 60% front weight distribution (roughly the same as my Ranger) so I ditched the equipped power-steering, and went with a manual conversion and a Flaming River steering box.

A new steering box fixed the worst of the dead steering. Image from www.flamingriver.com

The quicker ratio box almost eliminated free-play. I found that impressive, considering the box and steering wheel are joined by a lump of rubberized sailcloth with the stiffness of a Whopper with Cheese. I have yet to replace the rag-joint with the polyurethane piece I have, but I think it will eliminate what remains of the steering play. Despite the cost of the Flaming River box, it was the best and cheapest solution short of fabricating or shelling out thousands of dollars for a rack-and-pinion setup.

The final pieces were a set of 620 lb/in front springs and a set of shocks. Future upgrades will include a new set of rear leaf springs, a thicker front anti-roll bar, possible Panhard rod or Watts linkage, and fully adjustable shocks to afford me some modicum of tuning capacity. The new front suspension responds well to added camber, and the kit comes with suggestions for inital setup. Once Operation EFI has been completed, the Mustang will stretch its legs at a local track, in an attempt to evaluate the effectiveness of the modifications, both to the suspension and to the induction system.