That would suggest that the resistance of the leads is 0.2 ohms and your coil is OK, unless it changes when it gets hot or something.

Are you using a Pertronix ignition module or Mopar or something else?
Can you duplicate the problem pretty easily?
When it runs, does it run roughly or smoothly?
Do you have a timing light?

The ignition module is Mopar as far as I know. It runs sort of rough at idle, but at higher RPMs its pretty smooth and its been that way since I bought the car and with the old coil. Yes I have a timing light.

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'74 Duster 225 Super Six w/904
14" Cragar SS wheels

Here's a trick I use to diagnose problems: hook up your timing light and instead of looking at the timing mark look at the blinking light to see if you have a spark. You can do this on each plug wire to see if the problem is isolated to some cylinders and not others. You should try this while its running bad if you can. I can tell by watching the blinks if the spark misses part of the time.
While you are there you might as well check the timing too.

Thats a great idea, and if I remember, the timing is pretty jumpy, could that be a cause?

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'74 Duster 225 Super Six w/904
14" Cragar SS wheels

You cannot reliably check a coil only by it's resistance; often, old coils often start arcing internally. A scope will show the problem, but it can also be very intermittent. A new coil is a very good idea if your old coil has over 1,000,000,000 sparks on it (#sparkes ~ 3sparks/rev*#rev/min*60min/hr*total.miles / avg.mph).

I've never seen a ballast partially fail; for me they always failed entirely open, but I've seen many coils, sometimes even new ones, get flaky.

I've also seen the same symptoms from a flaky coil-to-distributor wire - checked perfectly with a multimeter, but would give problems only now and then until it finally failed totally. The other wires may cause you to loose 1 cylinder, but that one wire can cause you endless grief.

If the timing is jumpy you probably have a worn timing chain.