66 Dart wheel question, carb/iginition

I replaced my mopar electronic ignition with one of these:

http://www.ebay.com/itm/Small-Block-Mopar-Dodge-Chrysler-318-340-360-Complete-Electronic-Distributor-HEI-/380453707588?pt=Motors_Car_Truck_Parts_Accessories&hash=item5894cedf44&vxp=mtr

The conversion included a flamethrower low resistance coil. I eliminated the ballast resistor, gapped the plugs to .050" and advanced the timing from 10 to 15 degrees btdc and my mileage around town went from 11.5 to 13. The added benefit was a more stock appearance and less wires under the hood since everything except the coil is contained within the distributor.

They also have them with the coil built right into the distributor cap but didn't look stock enough for my taste.

Just make sure you inspect the mounting of the ignition chip to it's heat sink. My first one failed early and I discovered that that the locating pins did not line up with the holes in the heat sink so there was not a good thermal bond. I shaved the locating pins off the free replacement chip and no problems since.