The Ford 4.9L Straight Six History

Written by rob wagner
  • Share
  • Tweet
  • Share
  • Email

The Ford 4.9-litre in-line six-cylinder engine, which displaced 300 cubic-inches, was a fourth generation straight-six engine produced by the automaker to power full-size automobiles, pickup trucks, tractors and multi-stop delivery vans. The power plant had a reputation for reliability and a lifespan of about 300,000 miles if properly maintained. Fuel injection versions of the 4.9-litre in-line six became available in 1987.


Ford began producing its first in-line six-cylinder engine in 1906, but it was such a poor performer that the automaker abandoned it in favour of four-cylinder versions until the V-8 arrived in 1932. Ford returned to the straight-six in 1941 with a flathead version displacing 226 cubic-inches for its cars and trucks. A 110-horsepower 254-cubic-inch version debuted in 1948 to power the F-series pickups and school buses. The automaker offered sixes displacing 215, 223 and 262 cubic throughout the 1950s until the Falcon Six became available in 144-, 170-, 200- and 250-cubic-inch displacements. The 300 in-line six was a big-block version of the Falcon engine and was available starting in 1964. It was an option for all F-series trucks and heavy-duty commercial trucks through 1996.


The 300, or 4.9-litre, big six featured several improvements over the smaller versions. It employed timing gears instead of a timing belt or chain. It featured a removable intake manifold and a high-flow heavy-duty exhaust manifold. It was the only straight-six to have fuel injection. It wielded more torque than many V-8s with a maximum range of 283 foot-pounds. The engine was so versatile that factories used it as a stationary power plant and to power ski lifts, wood chippers and airport baggage belts. For many years, it powered United Parcel Service multi-stop delivery vans and trucks.


The engine produced from 1965 to 1972 and equipped with a single-barrel carburettor developed 170 horsepower and 283 foot-pounds of torque. Its bore was 4 inches and the stroke measured 2.98 inches. It had an 8.9-to-1 compression ratio. Horsepower then dropped dramatically as Ford detuned its engines in response to stricter federal emission control regulations. The 1973 and 1974 versions developed 101 horsepower and 223 foot-pounds of torque as the compression ratio fell to 8-to-1. Output climbed to 120 horsepower in 1975 and then varied from 101 to 120 through 1986 after fuel shortages had griped the United States in 1978. With the introduction of fuel injection in 1987, output rose to 145 with 265 foot-pound torque rating. The compression ratio also increased to 8.8-to-1. During its last two years of production from 1994 to 1996, it generated 150 horsepower and 260 foot-pounds of torque.

Common Issues

Although the 4.9-litre in-line six-cylinder engine was one of Ford's most reliable motors, there were some common problems with the carburettor versions. Carburetted models were subject to vacuum leaks, which caused a rough idle or hesitation when accelerating. Ford trucks equipped with automatic transmissions and the 300 were sometimes prone to overheating. Engine overheating was usually resolved by installing an auxiliary fan and cross-flow radiator.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.