[AlfaGreg]

Hi John

My Crane XR700 is an optical trigger points replacement module using a shutter wheel and pickup in the distributor. I do not have points. This unit has a green LED that illuminates when the trigger is activated or "fired" so to speak. Used on its own to fire a coil, it requires a ballast resistor when the engine is running.

However, in my application, it is used to trigger the MSD 6AL. This in turn sends the optimal voltage to the coil and I tell you, the results are great.

This combo has been used sucessfully with a Bosch Red coil with an external ballast resistor in a racing application for many years.
I think you are right to do a coil replacement as the first step in eliminating the problem. MSD are not too fussy about coils and say it will work with any stock unit, but note that an oil filled coil must be mounted upright.

So I'll try that and go from there.

Thanks for the help.