[1] This layout came about because Vauxhall had originally planned to develop a whole family of engines all built on the same production line.

It also means most of the engine is very easy to access for maintenance, with the exception of the exhaust manifold and spark plugs, which are "underneath" the slanted cylinders.

Blydenstein Racing developed a long stroke version with a capacity of 2,600 cc (158.7 cu in) capable of producing almost 250 hp (186 kW).

Having been designed to withstand the stresses of diesel compression ignition, the block is immensely strong and able to handle large increases in power without modification.

Running prototypes were tested before the project was abandoned due to cost and the impending merger of Vauxhall's design and engineering pool with that of Opel in Germany.

Although arguably more technically advanced, the Slant-4 was considered less reliable than its continental GM counterpart, the Opel CIH (Cam In Head) engine.

The Lotus 900 series engine block was cast in aluminium alloy instead of iron, which made it considerably lighter than the Slant-4.

Engines with Lotus heads were used in Vauxhall's dealer team race and rally programmes until the late 1970s.

[4]: 248  To address the production shortfall Vauxhall approached Cosworth and had them produce the 400 cylinder heads needed for the racing homologation requirements.

[7]: 83, 84  When the new Vauxhall heads appeared in the Chevette 2300 HST the other teams complained, which led to a homologation scandal.