Fresh Startup Procedure.

Mmmmmm.... you have better test the ignition voltage to the MSD while running. It should only be no more than .5 volts lower than the voltage measured across the battery terminals. The ignition switches can go bad, but the wiring through the bulkhead connections in the firewall is a VERY common place to have voltage loss; the terminals get corroded badly. You had better check that and the connections in and out of the ignition switch.
It was the battery. The bulkhead is brand new. I will check but I have bigger problems now. The passenger side-rear where the intake meets the block meets the heads is leaking oil down the bellhousing and on to the headers. Not sure how to fix that short of taking the intake off.