340 balancer timing marks

str12-340 said
Sorry if you got that impression from my post. If you have the 70 and up set up, the timing marks are cast into the timing cover on the drivers side and they will be correct for harmonic balancers with a mark for 70 and up engines. It is my impression that all the aftermarket balancers that I am familiar with come marked for the 70 and up set up, or come with two crank keyways to be used for 70 and up and 69 and down.

I think that's correct. The ONLY exception I know of is either good used (if there is such) OR NOS such as from AMS (Frank Mitchell Mopars). But the NOS ones are still DECADES old and the rubber inertia ring is subjected to the same deterioration as any of the rest.