ignition problems

[LadyZ]

I have a 1973 240 Z with the following components: MSD 6A, mallory distributor and plug wires, NGK Iridium spark plugs, pertronix ignitor II and Flamethrower II coil. The car failed to start a couple of weeks ago. I replaced the points and coil with the pertronix units and the plugs with new Iridium units. The Pertronix was wired according to the MSD instructions using the ballast resistor to ensure a proprer signal to the tach. The coil generates spark, however the plugs aren't getting it. Specifically, they did get spark, then abruptly stopped after one last bright spark. The only answer is either wiring, which i went over with a fine tooth comb, or the pertronix unit. The last weak link is the ignition switch, which has been acting sketchy, but that does not expain how the coil is getting a signal from the MSD and sending it down the wire. Again, it all leads back to a problem in the distributor, but the only thing in there is a brand new pertronix. Anybody runnning this setup? Any suggestions? Bear in mind I have looked at all of the "simple" solutions (wires, power supply, polarity etc.), but at this point any advice is welcome.