LA318 stock to mild build harmonic balancer suggestion.

A local shop in your area might be able to replace the rubber ring and save you some money. Otherwise Summit has on for $100 but read the reviews before you buy.

1969 DODGE DART Summit Racing SUM-163273 Summit Racing™ OE-Style Harmonic Dampers | Summit Racing

I think you can use this one with no weights bolted on.

Professional Products 80012 Professional Products PowerForce Harmonic Dampers | Summit Racing