I have one of those distributors on my 65 273. I went with a Flame Thrower II coil for a stock appearance. The car seems to run better and my gas mileage went up 2 mpg over the Mopar electronic ignition I had (orange box), although to be fair, I also advanced the timing 5 more degrees when I installed the distributor. With the full 12 volt coil I'm running my plugs with .050" gap.
I did have a failure of the ignition module chip after a few months. Skip White sent me a replacement chip for free. Normally they're $10. Or you could just keep a second distributor in the trunk. When I went to install it, I found that the locating pins on the chip did not line up with the holes in the heat sync. This would prevent the chip from having a good thermal bond with the heat sync and probably led to the early failure. I shaved the locating pins off the new chip with a razor blade and installed the chip with some PC thermal paste. It hasn't failed since although I only drove it maybe three more months before tearing the car down for the restoration.
My advice is to take off the chrome cover and inspect the mounting of the chip to the heat sync. If there's not a tight fit, pull the chip off and shave off the pins. The thermal paste should still be there and as long as it's not hard, you can just reuse it, just don't wipe it off. If it's hard, you can get more at a Best Buy or Radio Shack. It's used in computers between the CPU and the heat sync.