440ci refers to the engine displacement of a 440 cubic inch engine, which was a common V8 engine option in Mopar (Chrysler, Plymouth, and Dodge) vehicles in the late 1960s.
4-speed refers to the type of transmission in the vehicle, in this case a 4-speed manual transmission. This means that the vehicle has a manual gearbox with four forward gears and one reverse gear.
1968 refers to the year the vehicle was manufactured. So, a 440ci 4-speed 1968 Mopar would be a Mopar vehicle from 1968 equipped with a 440 cubic inch engine and a 4-speed manual transmission.