Ignition voltage creeps higher and higher without car running

[68charger440]

I have been chasing ignition gremlins for awhile and need some help.  When I turn the key to the run position without starting it, the voltage to the coil seems to creep up over the course of 5 minutes from 7v to 11 or so.  I did the 70s style electronic charging system conversion a few years back and I am running an MSD ignition with the ballast resistor bypassed.  The car seems to have  a hard time starting when the voltage is low but seems to start easier when the voltage is higher.  What could cause the voltage creep when there is no ballast resister?  My meter is old and cheep, so it may be off.