Internally balanced 340 questions

The early 340 neutral harmonic balancer and the later 340 neutral harmonic balancer are balanced the same. The difference is the timing mark's are in different places so the timing covers are different to allow for this change. All cast crank 340s use the same external balanced harmonic balancers.
Do the 68 and the 71 use the same pulley bolt pattern? 72 bolt pattern is different from the 68. Easy fix with a rat tail file.

340 balancer lesson for the day.