In typical Chrysler fashion you can’t get a straight answer. I have never seen a MODEL YEAR 72 340 with a cast crank.
The text infers all 72 340’s has forged cranks, but the chart says a cast crank is possible in 72. Again, I’ve never seen an actual 1972 model year 340 with a cast crank.
@yellow rose , IIRC the transition took place mid-year 1972. My first '72 was built in October, which may explain why it left with the cast crank an 1.88 J-heads.