 In the same design range were the 4 and 5 types with smaller bore sizes and the 29 type with larger bore sizes.These were replaced with the 74, 75 and 89 and then, later, by the 274, 275 and 289 types.The 'Monobloc' type was available from 1955 with designations 375, 376 and 389
The more modern "Concentric", developed and introduced for the 1967 Model Year, was initially designated 600 and 900.