Refresher please on harmonic balancers

[Hopalong]

While moving a pile of junk from one spot to another, I came across a harmonic balancer I had thought was lost long ago.  I know it came off of a 72 340.  Now for the questions:  Was 72 the last year for forged cranks in the 340?  What else would this balancer fit?
Thanks

[Chryco Psycho]

72 should be a steel crank , the balancer will be weighted & clearly state for "340 cast crank" on it if it was off a cast crank engine