Why Littorio's turrets would not readily become French quads

Could Littorio-class barbettes accept Richelieu-style quadruple turrets?

Not without major redesign; the Italian barbette supported different loading priorities, and forcing in four guns would compromise operation.

The Italian arrangement used its available space to support loading and firing speed, so fitting a French-style quad would require new breeches and handling machinery. Similar barbette diameters do not make complete turret systems interchangeable. The panel expects Littorio's nine guns to sustain a stronger practical rate of fire than a crowded conversion. This comparison shows why magazine, hoist, breech, and working-space arrangements matter as much as the visible gunhouse.