A balancer only does one thing, it is designed to absorb harmonics. It does the same thing as a screen door spring wrapped around a long shaft when you are machining a long shaft, it absorbs harmonics. If I was balancing a lower end I would want to have or know what balancer was intended for use on the engine. In the case of your 327 I would guess that if your machinist didn't have the balancer handy he took into account the original type balancer when he balanced the assembly. I would stick with a stockish balancer if It were a street motor. If I were racing it I would go with the smallest balancer that would do the job.