appearance of a 340 vs. 360

Also need to note, that the 1973 340 was externally balanced, same as the 360.
The 340 external harmonic balancer will have the phrase "FOR 340 CAST CRANK" , cast into the front side.
Some very late 1972's & all 73 340's had cast cranks.
It looks like Chrysler used the cast 318 crank in these engines to save a few bucks before they went to the 360 for 1974 A-Body.