balancing a 440

As a '67 it will have a forged steel crank and was intrenally balanced from the factory. IMO - I don;t build any engine without internally balancing it. Doing it this way is usually more expensive - sometimes 50% more than a similar external. But - we're talking maybe another couple hundred. For that money spent you get longer parts life and more longevity, more power and efficiency at any rpm level, a smoothness that you can feel, and the ability to swap bolt ons like balancers and flywheel/torque convertors with any nuetral units. The factory started externally balancing because the crankshaft counterweights became too light when the crank material was lowered to cast steel.