Always big thanks for your replies. Mine is a 67 so I am not sure whether vibration damper applies. However, in search of this particular part within the pubs I have been less than successful. I do not see it in either the parts guide or the service manual in engine sections. Am I looking in the right spot? I have a video of the motor dynoed and the guy is all over it with a timing light. I will run my timing light on it to see if I can get a good reading.
Is dropping the trans by itself a hard procedure? That bell housing seems hard to reach.