It was a gradual deterioration. I replaced the carb,after replacing everything from the gas tank to the carb, then distributor,wires, plugs, then timming chain, and intake in that order.I was trying to eliminate problems and change suspect old parts. The Pertronix was put in place of the points distributor, that had a defective vac advance. Timming chain was replaced when I dicovered the timming was jumping back and forth. I decided to change the intake at the same time, since the front end was apart, and take a little weight off the front. I had thought at one time I might have internal issues, possible burnt valves or sticky valves, not sure. It has been about 25 yrs since my last Mopar (681/2 Super Bee) but man this car has me stumped....I like to tinker but this is really driving me crazy because the car is top shape otherwise.....case of the beautiful car that doesn't run well, and hard to get help here cause Hawaii is 90% Chevy muscle which is fine, I traded my 69 427 Vette for this car. I know it will get resolved, thanks to everybody for their advice.