I have finally found a vendor who sells new aftermarket harmonic balancer replacements for the inline 6 cylinder engines. However, I am uncertain of which one I should get.
I have a 1967 292.
Steve's specialty parts lists a balancer for the 292, but it is for years 1975-1989. He also lists two balancers for the 250, one of which is for 1967-1971.
Does anyone know if the balancers where the same for the 250 and the 292? I am sure any of them would be fine for eliminating harmonic resonance, but the pulley spacing appears to be different on all of them.