340 Harmonic Balancer Recomendation

Looking to purchase a harmonic balancer. If you have good/bad experience and recommendations I would like to hear from you. I believe its got a cast crank (1973 Block but was rebuilt) so it needs to be an external balance or come with weights for internal/external option.. This is for a street application and the set up is an automatic 904 with 355 rear sure Grip.

Thanks