Two years ago I purchased a 1966 122s in the summer. I used it as a daily for a bout a year. As I am not a mechanic I am not sure how to exactly describe the issue. The car starts and idles with no issue (providing it is not cold). However, it sounds very choppy, it does not missfire, but it does sound "imcomplete" or imbalanced and rough as if it was running on 3 cylinders. The car feels as though it is very down on power and often struggles to accelerate to pass, or make it hills during my daily commute that it other wise would have. I took it to my mechanic he did an oil change and a basic tune up. He cleaned and adjusted the carberators and made sure it was running on all four cylanders (which it was). he is unable to diagnoise the issue, and I certainly am not skilled enough to either. Any suggestions as to what it could be?