Shake rattle and roll
I believed so as well, but I have a nuetral balance converter with the flex plate that came with the motor and a factory magnum balancer. I have ran the engine with no belts and still the same issue. Also the issue isnt consistent. Sometimes it wont happen until the engine is warm sometimes you can barley feel it and sometimes it is so bad you dont want to drive it down the street. Not sure where to go from here.