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Pontiac


Pontiac Logo

Pontiac is a brand of automobile that is part of the General Motors group. In the GM brand lineup, Pontiac is a mid-level brand marketed in a way to promote a more sporting, aggressive, youthful feel to its advertising.

The Pontiac automobile line was introduced by General Motors in 1926 as a lower-priced version of their Oakland Motor Car line.

The Pontiac Logo was originally meant to represent an Indian (Native American) arrow-head, and early slang for the vehicle was to call it an Indian. Also an Indian/Headdress logo was used for a while.

Contents

Notables

The Pontiac GTO, originally an option on their LeMans/Tempest body, a GM A-body car, famously with their Tri-Power setup of three two-barrel carburetors. GM was weary of putting a full-sized engine in a compact car, and the GTO struggled against this its whole life; however doing so launched the era of muscle car.

The Pontiac Firebird was an F-Body car that closely mirrored the styling and motor offerings of the LeMans/Tempest cars, but in a smaller, sportier platform, and usually a smaller engine. This body style was shared with the Camaro, but until the advent of the unified GM engine, they were completely different beasts.

Just about the time that these muscle cars were getting big attention, emissions regulations and oil shortages quickly ground them to a halt. While production first started in the late 1950s, it did not hit its stride until the late 1960s. By 1972, few were left on the market.

Engines

Pontiac's Second Generation V-8 engines were nearly identical, allowing many parts to interchange from its advent in 1958 to its demise in 1979. Sizes ranged from 326 cid to 455 cid. There were only a few oddballs such as the 301 that relied on a different engine block. This similarity makes rebuilding these engines particularly easy, as almost any Pontiac engine you can find will contain useful parts.

See Pontiac V8 Engine

All Pontiac Motor Division (PMD) engines (pre 1980 unified GM) were designed around a low-RPM/high-torque model, as opposed to the ubiquitous Chevy Small Block known for its smaller displacement and high-RPM/high-horsepower design. Those who argue that the Chevy is better because it is more "powerful" know not what they are talking about, as each engine may be harnessed in different ways to achieve the same times in a drag race. It is also worth noting that the early Chevy engines were budget engines with poor quality metals in the block requiring extra bolts and support to keep from flying apart, while the other GM divisions used a much higher quality of metal.

PMD engines were unique for their rear distributer, integrated water pump and timing chain cover, and separate valley pan and intake.

Carburetors

PMD originally used Rochester 1bbl carburetors for many years, but by the time of the second generation engines had switched mostly to the 2bbl offerings. These were the basis for the Tri-Power setups on the engines.

Tri-Power included one center carburetor with idle control and two end carburetors that were not to open until part throttle. This was accomplished two ways, mechanically for the manual transmission models, and via a vacuum-switch on the automatics. This went through various permutations before being banned by GM.

PMD also had a square-bore 4bbl at the time, but this was rated at a lower horsepower then the Tri-Power. This carburetor was later replaced by the Quadrajet , a spread bore. Spread-bore refers to either the distance between the primaries or to the difference in sizes between the primaries and secondaries.

By the end of the Muscle Car era, the Quadrajet had become the nearly-ubiquitous choice on PMD engines, due to its excellent economy and power characteristics. While it has been derided by many as a poor performer, many have shown that with proper understanding, it can compete at most levels with other designs.

Similar carburetors include the Thermoquad and the Q-jet. This design proved good enough to last well into the eighties with emissions modifications while most others carburetors were dropped for the easier to build fuel injection when economy mattered.

See also

External links

Last updated: 08-24-2005 20:12:05
Last updated: 08-27-2005 21:09:27