Cranks but doesn't start using the key. Starts when using a remote starter switch.

Has it been converted to electronic ignition, or a better question, WHAT IS the ignition you are using, AKA bone factory stock breaker points, or "some other", or some sort of electronic, and just what is that?

The IGN2 ballast bypass circuit is a great place to start as posted above

HOW THEY WORK (And I **** canned a potential friend who refuses to understand this)

IGN1 is the "run" voltage source at the ignition switch. It is ONLY hot in the "run" position, that is, IGN1 goes DEAD during cranking

During cranking, there are TWO switch contacts which are hot---the "start" terminal which operates the start relay, and the IGN2 contact which runs to the coil+ side of the ballast resistor. THAT is what powers the system for starting, and sends full battery voltage to the coil +