Did you put new points and set the dwell angle to spec?

Possible cause is the points are #### and cause to much resistance for anything less than 12v

First off, thanks to everyone here for helping a 1200 newbie out. I appreciate it immensely.

I have a strange one. My car ran fine when I first got it a few weeks ago. It started running bad, so I checked the points and all appeared fine. Still running bad (after warmup) I replaced the cap, rotor, and wires. Still does the same. (The spark plugs look great)

On a whim, I installed the ignition coil out of my '79 A14 and my car ran great all the time. I ordered a new coil, and it reverted back to the same old problems. I then replaced the ballast resistor, and the same symptoms appear.

The new coil is marked 12v and says it is to be run using a ballast resistor. My '79 coil should be a 12v also, but that system has no ballast resistor.

Any ideas why it runs bad using the coil designed for the resistor? Will I damage anything using the non-ballast resistor coil?

I am open to any suggestions. This one has me a bit baffled...

Thanks again!