On November 17, 1928, General Motors turned the low-priced field upside down with the introduction of the 1929 Chevrolet six. 

The man above in the sporty straw hat with his foot on the running board of the ’29 Chevy is William S. Knudsen, the president of the Chevrolet division of General Motors from 1924 to 1937. Henry Ford’s former manufacturing boss, Knudsen commanded Chevrolet’s drive to the top of the U.S. auto industry, muscling the Ford Model T out of its traditional number-one spot.

Knudsen had been hand-picked for the job by GM president Alfred P. Sloan, and together they executed a highly successful product strategy for Chevrolet: For just a little more money than Ford, they offered buyers far more in style and features. In late 1927, Ford finally responded to Chevrolet’s challenge with the vastly modernized and improved Model A. But Chevrolet trumped Ford once again in November of ’28, rolling out a six-cylinder model to compete against Henry’s four.

Chevrolet’s new six-cylinder engine was developed by largely the same team that produced the groundbreaking 1926 Pontiac six, led by Chevrolet chief engineer O.E. Hunt and the brilliant Henry Crane, a consulting engineer who reported directly to Sloan. Thinking ahead, they began work on the Chevrolet in November of 1925, almost immediately after the Pontiac project was completed. (Read our feature on the influential 1926 Pontiac here.) While Sloan had conceived the Pontiac as “a six-cylinder Chevrolet” as he called it, he predicted that Chevrolet would soon need a six as well. In fact, Sloan could foresee that the inline six would soon dominate the American auto industry, including the low-priced field.

After considering various L-head layouts, the group finally embraced Chevrolet tradition and adopted an overhead-valve configuration with pushrods and rocker arms. The resulting design was efficient and advanced, with a mechanical fuel pump and automatic spark advance, yet still rather conservative, with three main bearings and a hybrid pressure/splash lubrication system.

With a bore of 3.31 inches and a 3.75-in stroke, the six displaced a tidy 194 cubic inches, and while it was slightly smaller than the 200 CID  four-banger in the Ford Model A, it was rated at 46 horsepower—six more than the Ford. And more importantly, with six firing impulses per cycle, the six was smoother than most any four-banger on the market. And now a key nugget of bow-tie lore: A number of external fasteners on the new six (and the chassis and body as well) were 1/4-20 (“quarter-twenty”) roundhead machine screws, as commonly found on kitchen stoves. And so it is that Chevrolets have been known as “Stovebolts” ever since.

Cautious nearly to a fault, Sloan could still feel the sting of the Copper-Cooled Series M Chevrolet fiasco only a few years earlier, and with the guidance of Knudsen, the division took a more guarded approach to the Chevy six rollout. The chassis for the new car was actually introduced one model year in advance as the 1928 Chevrolet AB National, with four-wheel brakes and a lengthened 107-in wheelbase to accommodate the longer engine that was scheduled to arrive the following model year.

With the removal of a fan shroud and the addition of a recessed firewall panel on the improved chassis, the new six-cylinder powerplant dropped right into the space previously occupied by Chevy’s trusty OHV four, thus creating the 1929 AC International. This graduated phase-in of the six-cylinder model proved to be far more efficient than Ford’s approach: a complete shutdown of the Ford empire for six months to switch from Model T to Model A production. As a result, Chevrolet gained a tremendous advantage in sales.

Marketed under the banner “a six in the price range of a four” and priced from $525 to $725, the new Chevrolet was a sensation, changing America’s vision of what a low-priced car could be.  The rest of the industry would soon follow, and new car buyers would never again have to settle for a four-cylinder engine. Of course, Henry Ford was never one to follow, and for 1932 he went Chevrolet one better and introduced the revolutionary Ford V8. So maybe the 1929 Chevrolet six was more influential than we realize: If not for the Stovebolt, there might never be a Ford V8, either.