Rat Motor

GM production big block engines were known as Rat motors.

'W' Series:

5.7L 348ci - 1958 thru 1964
6.7L 409ci - 1961 thru 1965
7.0L 427ci (Z11) - 1963 Only

Mark IV (Gen 2)

6.5L 396ci - 1965 thru 1972
6.6L 402ci - 1970 thru 1972
7.0L 427ci - 1966 thru 1969
7.4L 454ci - 1970 - Current (Inc. GenV & VI)
8.2L 502ci - Late '80's thru Early '90's

Note: The 9.4L 572ci engine was not GM production except crate form, and the 502ci engine was only used in fleet vehicles.