Are you still using points? If so, RockAuto has two AC Delco coils that should be perfect. Coils

As to operation, the 'RUN' ignition wire that goes to the coil + terminal is a resistor wire. It drops the 12 volts to 6 volts to extend the life of the points. The other wire is from the starter solenoid + terminal. That gives a full 12 volts to the coil for better starting. When the starter disengages, it goes back to 6 volts.

Before HEI came out, when I ran points, I used the Mallory Volt Master coil. It was huge and worked great. I also used the Mallory Super Condenser. It was so big it had to be mounted on the outside of the distributor body. The points lasted much longer and performance was improved greatly.

You can still get a Pertronix points eliminator kit that replaces the points with a solid state ignition, and a more powerful coil. That way it looks stock but is much better than stock.