This is a high performace street car. Not a DD. I pretty warm 440 with a few bells and whistles. I bought a distributor this afternoon after i had gotten some feed back. It is a pro billet.
Sounds like my brotherin law's car. A 440 challenger with a large cam and double pumper carb and Mopar Performance ignition system with the advance pluged.. Ran like crap for 3 years and he couldn't get it to run right untill he hooked up the advance. Ran a like a differerant car then.
He seen all the performance dist. without a vacuum advance so it should be good for his car too, right? Wrong.
See if you swap that dist. for a vacuum advance unit, you can always plug it if you want to.
Good luck!