My 1970 `Cuda 440-6 had an engine rebuild in the early 1970s, and the transmission replaced in the late 1970s. I bought the car in the early 1980s, and the time has come to rebuild the transmission. The guy doing the work called to tell me the torque converter has no weights or other signs of balancing... I am having him remove the oil pan to look for any indication the engine was neutral balanced when rebuilt in the early 70s.

My Question - How severe would the vibration be if the engine was still set up for external balancing, but a neutral balance converter had be used in the late 70s rebuild...???