[Rossba]

The MSD likes 10volts or more or it won't fire under crank.
Often it will crank and crank then when you stop the crank it does a quick fire just before you turn the ignition off.
We have had lots of MSD blaster coils fail so have upgraded them to to E core.
There are numerous people having trouble with MSD products and are going back to basics.
If you battery is dead try it with the new battery.