GMC Straight-6 engine

GMC only ever "owned" two engine designs, this straight-6 and a V8. The company "borrowed" many engines from other divisions, as noted below.

Non-GMC engines

In 1935 and 1936, GMC used Chevrolet's 207.

From 1937 through 1950, GMC used Oldsmobile's 230.

In 1938, GMC used Pontiac's 223.

From 1963 through 1978, GMC had its own distinctive version of Chevrolet's straight-6, the 292.

GMC replaced the Pontiac 223 with their own 228 in³ (3.7 L) 228 in 1939. This side-valve engine was produced through 1953.

GMC also developed an OHV/pushrod engine in 1939. The 236 in³ (3.9 L) 236 was the first, lasting through 1955.

Those same years (1939-1955), GMC produced a 248 in³ (4.1 L) engine, the 248, which was similar to the 236.

The 256 in³ (4.2 L) 256 was different from the 236 and 248. It was also an OHV/pushrod engine, and was built for just two years, 1940 and 1941.

The last GMC-only straight-6 was the 270 in³ (4.4 L) 270. It was produced from 1941 through 1962 and was an OHV/pushrod engine.