Chrysler Corporation in the US had been working since 1966 on an inline 6-cylinder engine, called the D-engine, to replace the Slant 6 (G-engine) in Dodge trucks, but abandoned the effort after prototypes were built.

The agency managed to fly Moss to Adelaide in secret for the advertising campaign, surprising Chrysler Australia's executives.

All Hemi-6s share a robust crankshaft supported by seven main bearings, and this family of engines quickly developed a reputation for excellent performance, economy, and durability.

The Australian Hemi engines were designed by a five-man team which included the late Maurice Harcus.

The increased power is due mainly to a more aggressive camshaft, high-load valve springs, triple 45 mm (1.8 in) DCOE sidedraught Weber carburetors, tuned-length exhaust headers and a higher compression ratio of 10.0:1.

Specifications (for 2bbl carbureted variant): This economy-orientated version of the Hemi 6 was released as a running change in early 1971 as the base model engine in the VH Valiant.