1969 Valiant, 340...TCI 727...8 3/4 w/3.55

I think oldschoolcuda is correct, I have a 72 demon that has a vibration in it. I purchased it from original owner who tells me he broke the crank years ago and it was replaced under warranty by the dealer after that it has had the vibration every since but they refused to repair it. So thanks for the info that way I may be able to correct my problem also.