I think it means 456 mm per cylinder, which I think is the way Ferrari's vintage cars were designated.
+1. But I think the measurement would be in cm. (cubic) Another close resemblance to the number is that it has 4 seats, and almost displaces 5.6L. But this isn't the reason behind the name.
Nope, 456x12=5472 cc. Displacement actually 5474 cc, each cylinder displacement 456.159 cc. Displacement per cylinder was the historical way Ferraris were named in the olden days. First 125 V12 was a 1500 cc car, the 250 V12 series were 3 liter (3000 cc) cars, 500 series I4s were 2 liter cars, etc. After the 456, this naming system has been abandoned, unfortunately.
Anyone ever done the math on what the new designations should have been had they followed Enzo's rule? I'm guessing the V8's numbers would be in a similar range to the V12s, i.e., the F430 would be the "538" and the Italia, "563." But then the 599 would only be the "495." Come to think of it, maybe we're better off.
Dave- Have to add the electric motors' diameter or the volts per motor or something suitably arcane. Number of windings per motor?