1961 Chevy Truck Harmonic Balancer

I recently bought some alluminum pulleys to dress up my 350 small block engine, I installed a new thwater pump pulley, and the lower crank pulley. After starting up the engine I noticed that the harmonic balancer had a slight wobble to it from front to back about an eighth of an inch, I have never noticed this before and wondered if there is any amount of wobble in the balancer that is exceptable?