You have to have a 6 cylinder distributor for a 6 cylinder engine.
Far as I know the B30 distributor is the only one that is a direct
replacement although there might be others that could be adapted.
That would definitely be the hard way.
You should find out what it wrong with the distributor rather than just
replacing it.

The Zenith-Stromberg carbs say "Zenith-Stromberg" on top of the diaphragm
housing.

Not knowing what carbs it has it is hard to say what issues it might have.
In any case, recent experience indicates that you should, at a minimum, drain
the gas tank and put in new gas. Then see if the fuel pump delivers fuel
to the carbs. Sometimes they get gummed up or get particles of dirt or rust
in the valves in the fuel pump.
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George Downs, Bartlesville, Oklahoma, Central US