Ignition problem: starts and runs in neutral but dies off in park

Ballast is still in place. I put everything back the way it was before the engine swap. No wires got swapped - the only thing I did when I bypassed the ballast resister was fashion a pair of short wires with spade terminals and connect the two connectors.

Is there an easy way to jump the neutral safety switch?
Yes, but before you try to run yourself over, try applying straight 12 volts to the distributor. (You said Skip White HEI, is that the big GM coil in cap style?) Or, direct 12 volts to the + side of the coil and see how it runs.
Don't leave it hooked up to long with out the engine running.