My guess is it's your magnetic pickup!
Go to the MSD site
msdtech@msdignition.com or call them (915) 855-7123
You will see how to check for spark and other troubelshooting tests
If it's the Mag. Pickup and you talk to them real nice they may mail you one "free" - - - it takes time to come by mail - - so you can by them at your local Auto Zone
To replace the pickup is not a hard job if your somewhat car smart! the pickup is siliconed glued in place and breaking it loose is the hardest part - -the new one dosent need to be gluded back in.
Hope this helps!