Jim Smart
March 9, 2011

Ignition & Electrical

We take our ignition and electrical systems for granted as if they happen by magic. A Mustang's electrical system follows the fundamental laws of physics and there are no exceptions. Fall short in your electrical and ignition system planning and you can count on winding up roadside.

The first area to address is proper grounding. We will even suggest taking grounding even further than Ford because it's that important. Because your engine and transmission sit on rubber mounts, they must be grounded to the firewall in order for both ignition and charging systems to work properly. If you've converted your classic Mustang to electronic fuel injection, it's even more important to be redundant in your grounding program.

One old law of physics is electricity. It will always find the path of least resistance, sometimes with befuddling results. A poorly grounded ignition system offers hit-and-miss operation. Sometimes your engine starts. Sometimes it won't. And sometimes it will just quit. Charging may be intermittent with erratic voltage regulator operation. It is suggested you have two forms of engine grounding-the factory cylinder head to firewall ground and another ground from block to chassis.

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Don't forget distributor grounding, which is a small ground lead inside your distributor. Too many of us forget that little guy during tune-ups or PerTronix Ignitor retrofits. Because the breaker plate floats on nylon rub pads, you can't count on sufficient grounding any other way but the ground strap.

Ignition system selection depends on how you intend to drive your Mustang and the level of expected performance. Cruisers and weekend show cars are good to go with high-quality ignition points or a PerTronix Ignitor conversion, which eliminates old-fashioned ignition points. The Ignitor is the easiest upgrade you can make to a classic Mustang and it never requires maintenance. Install it, set the gap, and forget it.

If your Mustang project is more about high-performance driving, you may want to consider an MSD Ignition system or PerTronix's billet distributor, which is fitted with the new Ignitor III system for exceptional performance. Street Mustangs should get a distributor with vacuum advance, which helps the engine deliver both efficiency and low-end torque.

Regardless of the distributor you use, always have it curved to expected driving conditions. In other words, have a qualified technician set up your distributor for your engine and how you intend to drive. MCE Engines does complete distributor rebuilds along with proper tuning for your application. There are also other professional distributor rebuilders and tuners out there such as Tim O'Connor, a Ford service technician, who has been rebuilding and tuning Ford ignition systems since 1966.

Exhaust System

This is another area we tend to overlook. However, it is important to both performance and reliability. You want a low-restriction exhaust system, yet with enough restriction that will give you back pressure and scavenging. Velocity through header primary and secondary tubes along with low-restriction mufflers is key to the smooth flow of exhaust gasses and delivery of power. The choice of long- or short-tube headers depends on the amount of power your engine is going to make. As horsepower increases at high rpm, you're going to want long-tube headers. Shorty headers yield some improvement in exhaust scavenging because they do away with the restrictive roughcast surfaces and passages of stock exhaust manifolds. However, don't expect a huge gain in performance from shorty headers. Long-tube headers will give you better scavenging and velocity as rpm increase.

It can be challenging to choose the right type of long-tube headers. You want custom-tuned headers with uniform length primary tubes and right-sized collectors for optimum performance at high rpm. Yet, equal-length header tubes can make things a bit crowded. It is all about compromise. One of the best long-tube header manufacturers we've worked with is Ford Powertrain Applications (FPA), which offers Ford buffs perfect-fit long-tube headers with ball and socket collectors that don't require collector gaskets. These headers tuck close beside your engine to take up minimal space.

Muffler choice and pipe size depends on how much power you intend to make. Pipe size should be proportional to power output. Pipes that are too large will lose precious torque. Pipes that are too small will cause excessive backpressure and heat.

Another important consideration is cabin noise levels. Although loud exhaust systems have been fashionable with hot rodders for generations, we're also a generation of deaf people from rock 'n' roll music and hotrods. You want good sound deadening and user-friendly mufflers for your road-going Mustang cruiser.

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