So... What did I buy?

1967 - 1972 273 and 318 had a narrower connecting rod beam width and lighter then 340 , 360 rods. 1973 and later all had the same beam width rods.

But no forged cranks after 72. The forged crank you pictured is a pre 1972, 273. 318 That is why the journals are not drilled. Because it was from a narrow beam connecting rod engine.