1969 dodge charger vibration

[1969boxercharger]

so i have a 69 charger with a 440 that has major vibration...i was told that its caused by engine not being balanced,and that i shhoud replace the harmonic balancer. my main question is,,what specific information do i need of the engine so i can purchase the correct balancer. and does someone in here have a specific website or shop that can help me with this? thanks..

[303 Mopar]

Is your crank internal or external balanced?  This will effect the harmonic balancer and the flex plate.

[Draco]

  You will need as much info on the motor as possible. Especially what work has been done or modified. Is it auto or manual trans or has torque convertor been changed.

[Paul G]

Wow. Someone told you it was the balancer. Can you pull it off and press the new back on yourself? There very many things that can cause vibration.

[68 RT]

Could just be a motor mount or transmission mount?

[DAY CLONA]

Could just be a motor mount or transmission mount?

Also something as simple as 2 spark plug wires on the wrong plugs, confirm your firing order, as well as checking your motor/tranny mounts...costs nothing to confirm this