350 Buick Engine Specifications

by James Jordan
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Buick built a 350 engine starting in 1968, joining GM in the family of small-block V8 engines. Buick's 350 was different than the rest of GM's 350 engines. It had a wider bore inside the engine, which made it wider, and it had an external oil pump, which was unusual for engines at the time. The 350 was used from 1968 to 1980 in large Buicks.


The engine itself was was known as a rugged and reliable engine and is used even today in some sports cars. The engine was wider and had a longer stroke than other GM 350 engines. The late 1960s were the end of the muscle car era, and the 350 was a victim of their demise as well. When introduced in 1968 it had 260 horsepower. Rising emission standards and more concentration on fuel economy slowly sapped the engine of its power. By 1975 its horsepower was down to 150. The engine itself did not change. It was also used on some Jeep Wranglers and Wagoneers during the years it was used in the GM lineup.

Engine Details

The 350 was the small-block engine that had exactly 349.3 cubic inches and was a V8. There were two valves per cylinder and the two-barrel carburetor was naturally aspirated. The bore and stroke was 3.8 and 3.85 inches. This was a bit usual as the bore is usually a higher number. The bore and stroke refer to the width of the cylinder and the distance it travels. The compression ratio -- or the amount of compression on the air and fuel mixture before it is ignited -- was 9 to 1 in 1970 and 8.5 to 1 by 1975. The car came standard with an automatic transmission, and a manual was available.


As additional items were placed on the engine, performance suffered but gas mileage improved somewhat. In 1970 the Buck LeSabre, which ran the engine, was rated at 20 miles per gallon in city and 25 miles per gallon highway. By 1974 those numbers had risen to 22 and 26. In 1970 the LeSabre had 260 horsepower and by 1979 it was down to 155. The 1970 LeSabre was rated with a top speed of 117 and it could go from 0 to 60 miles per hour in less than six seconds. The 1979 LeSabre had a top speed rating of 110 miles per hour and it took just more than seven seconds for it to get to 60 miles per hour. The engine was discontinued for the 1980 model year.

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