One wire alternator problem

Recently I converted my car to a one wire alternator. It's a 71 swinger so it had the newer style regulator. I bought a tuff 1 one wire 100 amp Chrysler alternator from summit racing. I also bought an 8 gauge alternator wire. When I installed the alternator, I also grounded it to the chassis as per the instructions. When I removed the voltage regulator, I removed the field wires which splice into the ballast resistor. This was a good 12 volt ignition source under hood. I had my msd ignition wire spliced into the ballast resister wires. Shortly after the conversion, I started having ignition problems. The voltage at the ballast resister now fluctuates. I know the msd ignition source has to be 12 volt but why is the voltage fluctuating when the car is running? Its 12 volts key on. Then when the car starts, it jumps up as high as 16 and as low 0 which of course make the car die. The voltage at the battery is about 14 to 14.5 constant. The 8 gauge wire goes from alternator to battery.