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I am not getting spark to the plugs when I'm turning my 1937 120 engine over. I did research on the resistance specifications of ignition coils, mostly of the modern type. The resistance between the outside terminals should read between .7 and .8 ohms, but for a 12-volt system. The resistance between the output line to the distributor and the outside terminals should be between 10,000 and 11,000 ohms, again for a 12-volt system.
I am using a modern coil for 6-volts but the between terminal resistance is between .3 and .4 ohms, although I am getting readings between 10,000 and 11,000 ohms from the central terminal.
My question is, does anyone know if this reading between the outside terminals is normal for 6-volt systems since is it approximately hals of that for 12-volt systems? Im still looking at the condenser and points, but it is the coil output in which I am most interested at the moment.
Thanks.

Packard didn't give much info on coils other than amp draw. For 37 coils, the current for "idling" which I assume is points open is 1/2 amp and for "stopped" which is probably points closed is 2 1/2 amps. When testing all they used was a go or no go type coil tester so don't have any actual winding specs but approx half the value of a 12v coil doesn't sound too bad.

Have you verified coil voltage as measured to ground and the possibility of shorts? If pos ground, 6v or battery voltage should be at the negative terminal coming from ign switch. If the points are open 6v would also be on the positive coil terminal or at dist. If points are closed pos terminal should be low near 0v or no more than about 3/10 at the terminals. I would verify the points are closing and the positive or dist terminal is making the change. Also check that nothing in the dist is shorted keeping it at a constant 0 or a high resistance problem with the dist ground is not allowing the points to pull the terminal to a full low. Anything higher than 1/2 v with points closed needs to be looked into. When cranking, ideally the supply voltage to coil should not drop much below 5.5 v. If it goes much lower -- say close to 5v -- the spark will be weak and might not reliably jump the plug gap under compression.

The chances that no spark at the plugs is caused by a bad coil are relatively low. Just to eliminate the cap and rotor, verify that you have spark from the coil. Your most likely culprits, assuming good connections, are a shorted primary feed to the coil from the ignition switch, a failed condenser, or bad/misadjusted points.

A key question, is your ammeter indicating a current draw by the coil as the engine cranks?

Thanks to both of you for the information. I'll check this out.