Ever since iron was first smelted by primitive man, the metal has played an important role in human activities. Never before was such a strong and durable substance been available. It changed everything, especially the development of machinery. Naturally when the first internal combustion engines were being developed, iron played a major role.
The first engine blocks were made of iron, in particular cast iron. Cast iron allowed car manufacturers to make complex engine blocks with precisely-aligned cylinders, coolant jackets and shaft passageways. Not only that, the material was plentiful and cheap.

But engine blocks made of iron aren’t perfect. One of the main issues is that iron is heavy. Large engines, in particular, are very heavy and that means more power is needed to move them around. This, of course, takes more energy and the result is more fuel is needed.

Engineers have known for hundreds of years that a good alternate metal is available. That metal is aluminum. Aluminum offers excellent strength and the ability to cast it into complex shapes. Best of all, it is considerable lighter than iron and thus is an excellent choice for airplane and automobile construction. Negatives? Well, aluminum warps easily when exposed to high heat and it corrodes easily too. For these reasons and others, automotive engineers were reluctant to use it for many years.

In early 1960s, General Motors decided to give it a try, though. They built a 215 cubic inch V8 all-aluminum (heads and block) engine and put it in their Buick Special, Oldsmobile f-85 and Pontiac Tempest models. It had overhead valves and hemi heads. There were two versions: The standard two-barrel-carb engine with an 8.8:1 compression ratio making 155hp, and the four-barrel version, with 10.25 compression, which was good for 185hp. It was the lightest V8 in America.

The 215 all aluminum engine was produced for several years but advancements in thin-wall cast iron designs soon led General Motors back to cast iron block designs. In 1967, General Motors sold the manufacturing rights to The Rover Company in England. Rover needed a light but powerful V8 to replace its aging 3-liter straight-six. This engine was small and light, and powerful.

Through the years, Rover engineers made numerous changes to the all-aluminum 215 engine’s design, mainly to streamline its production. So successful was this lightweight engine that, by the time manufacturing of the 215 came to an end in the late 1990s, it powered not only Rovers but was also used by Morgan, Marcos and TVR. In  fact, the famous Australian racing company, Repco, used the 215 block as the foundation for the development of its 3-liter overhead-cam engine powering the Repco Braham Formula 1 Grand Prix machines.

Chrysler Corporation made an aluminum block version of their famous 225 slant six engine. According to York Chrysler of Crawfordsville, a local Chrysler, Dodge, Jeep, Ram dealer in Crawfordsville, IN, it was installed in passenger cars from mid 1961 through early 1963 model years.

Today, aluminum is still used in engine block construction but not as much as you would think. 95% of engine blocks being produced by General Motors are cast iron and 83% of the heads are the same. Executives say the issue is purely economic. Presently iron costs about 25 cents per pound and aluminum is about a $1 per pound. Combined with the fact that cast iron is more rugged and thermally-stable, it is likely to be the material of choice for automotive engineers for some time to come.