[5][6] Contemporary NASCAR-spec top-level cars produce maximum power outputs of 860–900 hp[7][8] from their naturally aspirated V8 engines.

[15] The 1949 Oldsmobile Rocket V-8 with a displacement of 303 cu in (5.0 L) is widely recognized as the first postwar modern overhead valve (OHV) engine to become available to the public.

However, the end of the Korean War in 1953 started an economic boom, and then car buyers immediately began demanding more powerful engines.

This killed many spectators, and resulted in a serious overhaul of the safety rules, which in turn prompted the building of larger, more modern tracks.

However, even without official factory support or the use of fuel injection, Buck Baker won in 1957 driving a small-block V-8 Chevrolet Bel Air.

[citation needed] In 1961, Ford introduced the F1 390 in a low drag Galaxie "Starliner", but 1960 and '61 championships were won by drivers in 409-powered Chevrolet Impalas.

It also became apparent that manufacturers were willing to produce increasingly larger engines to remain competitive (Ford had developed a 483 they hoped to race).

Also, even with heavy duty special editions sold to the public for homologation purposes, the race car rules were further modified, primarily in the interest of safety.

This is because race drivers and their cars during this era were subjected to forces unheard of in street use, and require a far higher level of protection than is normally afforded by truly "stock" automobile bodies.

It was called a "fast-back", and because of this David Pearson was the series champion that year with Richard Petty dominating 1967, winning 27 of 48 races (including 10 in a row) in the boxier Plymouth Belvedere.

As a result, the 1970 Homologation rules were changed so that one car for every two U.S. dealers had to be built for sale to the public to qualify, hoping to delay the use of aero-bodies until tires could improve.

NASCAR restricted all "aero-cars" including the Ford Talladega, Mercury Spoiler II, Charger 500, Dodge Daytona and Plymouth Superbird to a maximum engine displacement of 305 cu in (5.0 L) for 1971.

The 1973 oil crisis meant that large displacement special edition homologation cars of all makes were suddenly sitting unsold.

It can be said that 1992, with the addition of ground effect wrap-around type spoilers and more aerodynamic body, marked the beginning for non-stock sheetmetal and from that point forward, stock cars were quickly allowed to differ greatly from anything available to the public.

First popular in the United States after World War II, this type of racing was early-on characterized by its participants' modification of passenger cars in pursuit of higher speeds, hence the name.

The series was the brainchild of then-NASCAR West Coast executive Ken Clapp, who was inspired by off-road truck racing.

Stock car racing is a full-contact sport in New Zealand: as the rule book states, "contact is not only permitted, it is encouraged".

Stock car racing in the NASCAR mould (AUSCAR) had a following in Australia during the mid-late 1980s and through the 1990s, but with the advent of the Supercars Championship, which took up the bulk of the competitors, sponsorship dollars on offer as well as major television time, the Australian Superspeedway series shut down after 2001.

The majority of the NASCAR and AUSCAR racing in Australia took place at the 1.801 km (1.119 mi), high-banked (24°) Calder Park Thunderdome in Melbourne.

The Thunderdome, which was opened in 1987 and was built by multi-millionaire tyre retailer Bob Jane at a cost of A$54 million, was modeled on a scaled down version of the famous Charlotte Motor Speedway.

Since the early days of stock car racing in Britain the sport has developed into many different classes, from the destructive 'Banger' categories to the very sophisticated National Hot Rods.

In 2008, Ian Thompson Jr. became the first driver from Northern Ireland to win the Brisca F2 Stock Car World title since 1972 when he took the honours at Bristol in 2008.

This irregularity has since been proven to be a manufacturing fault with the control of the driver but the governing body have refused to reinstate Gordon Moodie as the winner in the record books.

The 2011 World Championship Final took place at Kings Lynns Norfolk Arena on Saturday 17 September with 871 Mark Simpson winner of the Gold Roof.

Licensed by Spedeworth, as opposed to BriSCA, Superstox are similar to Formula Two Stock Cars with the main visual difference being a smaller wing on the roof.

Stock Car Racing has existed in Canada as early as the 1950s in amateur format, although official structured competitions began with the foundation of CASCAR in 1981.

The highest local division, asphalt late model racing, is generally considered a requirement to advance to the next step, regional and national touring series.

Johnny Rutherford, a three-time winner at Indy, has the rare distinction of winning his first NASCAR start, a qualifying race for the 1963 Daytona 500.

Dan Gurney, a leading 1960s Formula One driver and later one of the most successful constructors of Indy cars (as well as being Foyt's co-driver at Le Mans), excelled in NASCAR's road-course events, winning at Riverside five times between 1963 and 1968.

Two-time Australian Supercars champion Marcos Ambrose competed in the Monster Energy Cup Series from 2007 to 2014, winning two races.