Recently I have been trying to get my Duster back in road worthy condition and while trying to pin point the cause of the irritating stumble in the motor, I finally did a compression test to find the number 1 and 7 cylinders only producing 75 and 90 while the others being from 140-155 in a mostly stock '71 360 I rebuilt years ago. I don't have a leak down tester but did put air to the cylinder by using a connecter used to hold the valves up for service, it is apparently the rings as air escapes through the valve cover breather. It puzzles me why two would go to hell, Broken ring? IDK just needed to vent. However in all the cylinders the compression was higher 15-20psi oiled vs dry.
