My Bianchi has a 55/13 maximum combo. My Motobecane has a 52/11 combo, both of which seem pretty standard for their respective eras. I'm pretty sure that makes the older bike taller by a bit. My uncle's current Bianchi has a 53/12 combo for its tallest gears. It's not a big difference at the top end, but look at the bottom end! Long cage rd's have been around a while, there isn't much reason they couldn't have 13/36 casettes in the 70s, they just didn't. People climbed with corncobs because they COULD, and a lot of people were good at it too.

Sorry, I'm a young guy feeling curmudgeonly. The more I ride old bikes the more I like everything about them except DT shifters themselves.