The Mercedes-Benz M100 engine was introduced in the 1963 Mercedes-Benz 600 with 6.3 litres, and later also used in the Mercedes-Benz 300SEL 6.3 from 1968 onwards, and even larger, in the 1970s Mercedes-Benz 450SEL 6.9.It featured a cast iron V8 with a single overhead camshaft operating sodium-filled valves (as are found in piston-driven aircraft) against hardened valve seats on each aluminium alloy cylinder head.