Engine Vibration Problems We get many calls on this subject. We balance ALL engines we rebuild. ALL Buick engines are counter balanced externally , that means one part of the flexplate/flywheel is heavier, the same goes for the Damper/Balancer. To make things worse different Nailheads have different counter weights. The 264-322 flexplate/flywheels are 1" larger than the later 1957-66 engines so those can only be used on the 264-322 but they have different weighted damper and flywheels so you can still get into trouble. The 1953 322 had it's own balancers, there were two of them, an early cast iron pulley and late was a damper with steel pulleys, both have no timing marks and different counter balance than the 1954-56 322. The 264 has a cast iron front pulley, has it's own counter balance.The 1957-61 364 has it's own balance (damper and flywheel) and lastly the 401-425 have their own balance. So you have all the correct parts and it still shakes? The flywheels have 6 holes equally placed to mount to the crank and so 6 different ways it can be mounted but only one way is correct! LIne up the guide hole..Another problem we have had is the the outer part of the 364-401-425 dampers spinning on the inner part making the engine vibrate, they have rubber between the two parts.. The Keyway of the damper and the timing mark should ALMOST line up, mark it inner and outer parts with a center punch when you have the damper off so you know if it has spun later. Lately ALWAYS torque the 57-66 dampers to 220 pounds! if you skip this step you will ruin the damper and the crank!