This is one is a little less popular, having a large external box to take up space in the engine bay, and being more expensive. It has some (tentative) advantage of being a capacitive discharge system, so it can give hotter spark, longer spark,or multiple sparks. The 6AL model has an additional rev limiter function.

This unit draws a little more current than standard ignition, 5 amps at 5000 rpm, and even more current at higher speed. The tachometer output is not directly compatible with 1965-1967 MGB current sensing electric tachometer or the 1968-1972 MGB current sensing electric tachometer, so an additional tach adapter unit may be required. The current sensing tach requires a few amps of current to work, which would be in addition to the current consumed by the ignition module. The 1973 and later MGB voltage sensing tachometers may or may not work with this system, so the additional tachometer adapter may or may not be needed there.

One customer reports problems getting the MSD tach adapter to work reliably with his 68-72 MGB current sending tachometer. MSD factory claims there are no problems, but retailers and installers say different. Nisonger offers a service to make your tachometer work with aftermarket ignition systems.

Setup with mechanical tachometer or no tachometer.

Setup with current sensing tachometer (1965-1967 MGB type).
Needs the tach adapter. May also need a power resistor (not shown)
in the red wire between tachometer and tach adapter.

Setup with voltage sensing tachometer.
May or may not need the tach adapter.

For more information visit the MSD Ignition web site