The MSD 6 Series Ignitions feature a capacitive discharge ignition design. The Alfa stock ignition is an inductive ignition. In an inductive ignition, the coil must store and step up the voltage to maximum strength in between each firing. At higher rpm, since there is less time to charge the coil to full capacity, the voltage falls short of reaching maximum energy which results in a loss of power or top end miss.
The MSD Ignition features a capacitor which is quickly charged (within one millisecond) with 460 - 480 volts and stores it until the ignition is triggered. With the CD design, the voltage sent to the coil is always at full power even at high rpm.
The MSD 6 Series produces multiple sparks for each firing of a plug. The number of multiple sparks that occur decreases as rpm increases, however the spark series always lasts for 20° of crankshaft rotation. Above 3,000 rpm there is simply not enough "time" to fire the spark plug more than once, so there is only one powerful spark.
My MSD 6 is triggered by points. I use the BOSCH distributor # 0 231 110 044 JF4 which has a two stage advance curve with a steep advance gradient below 2000 rpm. Starting o fthe engine has improved very much when using new NGK BP6E plugs instead of Golden Lodges. The MSD control unit is mounted next to the air filter housing.