How to Pick the Right MSD Ignition

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If you are familiar with old school-style cars, then you are likely familiar with the infamous MSD ignition. However, you may not be familiar with the full range of ignitions that the company offers. In this article, we provide you with the concise info you need to choose the perfect MSD ignition for your ride.

When constructing or restoring a classic hot rod, dealing with the ignition system can seem like a daunting task. Dealing with single spark discharge can be complicated enough. When you throw in multiple releases, it can quickly start to feel like rocket science. While we do not want to discourage anyone from restoring their car, we do want to stress the importance of knowing what you are getting into before you start.

So, if you are interested in installing a custom MSD ignition into your vehicle, you should know what it does and what type you need for your ride. Otherwise, the project will get very frustrating very quickly. Luckily, if you want to learn more about the different kinds of ignitions that MSD offers, then you came to the right place. In this article, we will go over the different types of MSD ignitions, and which one best fits the needs of your vehicle.

What Does MSD Mean?

Before we get into the nitty-gritty details, it is crucial that you first know what the ‘MSD’ in MSD ignitions means. The acronym stands for multiple spark discharge, and it refers to its unique design. Typically, when a factory installs ignition starts, it discharges the spark plug one time. The MSD ignition allows for the spark plug to go off multiple times. So why is this design preferable to a single discharge? What makes it so sought after?

The real reason lies in the specific type of engine your hot rod is using. In a typical automobile, a single spark is all that is all that you need to create controlled combustion in the cylinder of the engine thanks to the mixture of oxygen and gasoline. However, when you make upgrades on your hot rod’s internal parts for performance features, often the traditional spark discharge system is not powerful enough to run the enhanced system properly.

Hence, the multiple, and often more powerful, discharges from these systems. Practically, this feature will provide the hot rod with better horsepower and more responsive throttle control. The degree of this improvement depends on what types of ignition you decide to choose.

What Are the Different Types of Ignitions?

Here are the six types of ignitions that MSD Ignition offers. Keep in mind the company also provides kits and distributors.

MSD Digital 6 Plus

This model is one of the most advanced of all the MSD models available. The MSD Digital 6 Plus features a small RISC controller that can be used to check in on each different system status like RPM, voltage levels and trigger signals. This controller allows for more accurate on-the-go counter balances within one percent of the revolution per minute limit. Additional, the MSD Digital 6 Plus offers two different RPM limiters — one for staging with low limits and one for protection against over revolving.

Thanks to the manual rotary switch you do not need to carry extra chips. The single stage delay sequence can engage after twelve volts of energy are applied — a feature that makes it ideal for cars whose engine’s feature nitrous add-ons. However, you will need to connect it to the nitrous application via a starter switch or wire.

MSD Programmable Digital 6AL-2

Though the designers based the MSD Programmable Digital 6AL-2 off the design of the MSD Digital 6 Plus, it features some key differences — primarily regarding its output schematics. Instead of relying on manual rotary dials for revolutions per minute calculations, the MSD Programmable Digital 6AL-2 features ports that can plug directly into your computer.

As the name suggests, once you start the software on your computer or laptop you can begin to programme the ignition remotely. There are some other benefits too: the MSD Programmable Digital 6AL-2 is less bulky and heavy than its predecessor since it gets rid of a lot of mechanical components for digital. It also features not two, but three RPM limiters — one for protection against over revolving, one for burnout and a final one for the holeshot.

The induction fan allows for more appropriate control and more accurate systems with the model. Altogether, the MSD Programmable Digital 6AL-2 offers general improvements on the MSD Digital 6 Plus, for around twenty-five extra dollars.

Digital-7 Plus Ignition Control

If you want the power of the previous two ignition systems without the programmable customizations, then the Digital-7 Plus Ignition Control is perfect for you. The ignition system produces around five hundred thirty volts of energy and does so with less popular thanks to its coil technology. The REV limits are adjustable via rotors and feature a twelve thousand five hundred limit on the system.

An EMI filter on the device ensures that no electrical feedback occurs. The sparks activate in the cylinder with a specific crankshaft rotation of twenty degrees. Essentially this is the cheapest “upper end” model you can find — meaning its intended use is for more high powered cars, as opposed to street racers. As such, it offers an exceptional level of combustion and power at a fraction of the cost.


This no-frills ignition system is much beloved by the drag racing community. The most recent model features a spark energy increase of forty percent compared to the last model. Two terminal strips allow for direct wiring. Also, the MSD 7AL-2 comes equipped with a standard two REV control system; the model also features a handy LED light. This feature makes it easy to install the product or diagnose any wiring problem. This model can operate in cars with four, six or eight cylinder engines.


The MSD 7AL-3TM offers the same reliability as the MSD 7AL-2, but with more customization regarding on-the-go adjustments. Unlike the MSD 7AL-2, this model features three-step REV control: one for staging with low limits, one for protection against over revolving and one for protection against burnouts. It also features a four-step delay system.

If you want to include a nitrous fan with your car, then the MSD 7AL-3TM offers four separate stages which can activate independently of each other. Overall, this model provides more regarding plug-ins.


If your just getting started in street racing, then you cannot go wrong with the beginner level MSD 6A. You can use this system with cars and trucks, not high-powered drag cars. However, with the baseline street vehicles, the MSD 6A provides better throttle response time, improved starting time, few plug fouling instances, better fuel efficiency, and, of course, more power thanks to the multiple spark discharge system.

Unlike the other systems, the MSD six series is supplied from a custom transformer and then stored I the unit, which you can transfer to the coil at any RPM. As long as the vehicle’s electric systems run within a range of twelve to eighteen volts, this model will work with any hot rod.


This model is another streetcar model with a bit of an added kick. The MSD 6AL offers all of the same features as the MSD 6A, with a bonus. Unlike the MSD 6A, this model comes with a REV limiter for on the go adjustments. Altogether it offers the same power with a bit more control and safety thanks to the limit. The MSD 6AL is excellent for the beginner racer who wants more adjustable settings than the standard 6A offers.

Which MSD Ignition Should I Choose?

How to Pick the Right MSD Ignition

Picking your perfect MSD Ignition depends on how powerful your car is. A low horsepower street racer will require a different ignition system then top fuel racing car. Generally, if your vehicle has less than one thousand horsepower, you might be better off choosing something along the line of the MSD 6AL. This model will give you multiple spark discharges.

However, if you want something more involved, or need to fit a higher horsepower vehicle, then you might be better off going with the MSD Programmable Digital 6AL-2 which allows for more flexibility for cars with over two thousand horsepower and further customization with nitrous products. However, if your car has a crank system or distributors that lock-out, you might be better off with the MSD 7AL-3TM

He hopes this article was helpful during your shopping process. There are a lot of great ignition products offered by MSD Ignition. But that does not mean that every system will be the right fit for your specific hot rod. We recommend you do some more research and make sure before deciding on a product. Good luck with your project and have fun driving!

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