1973 duster 340 counter or neutral balance

The first cast crank was the '71 360. That was also the first year of production for the 360. The next one was the '72 400 and that was also it's first year. In '73 this plague was foisted on the 318 and the 340. The 318 could still be internally balanced but the 340 needed a little external help due to the large bore size. The harmonic balancer had "for cast cranks only" cast into it to give the line techs a heads up and prevent imbalance due to parts swapping. There is a theory floating around that there were some late production '72 340s with the cast crank. I'm still waiting to see one. The 440 was next up in '74 and last but not least, was the mighty slant in '76. Could be off a little since I was off a lot back then (it WAS the '70s). FWIW, I went to work at a C/P dealership as a lot jockey when I got my license in 1969. Left for greener pastures (Ma Bell) in '77, and if I had it to do over, would have stayed where I was since I was next in line for a Service Writer position.