The 1933 GMC used a Pontiac engine (200 cu.in.) for the first series and the second series used a "Buick type" engine (221 cu.in.). The 1934, 35 and 36 used a Oldsmobile engine (213 cu.in.). The 1937 used the Oldsmobile engine, but it was enlarged to 229 cu.in. The 1938 used the Pontiac engine, which was a 222 cu.in. In 1939, GMC went back to Oldsmobile engine. All engines listed above are for the light duty trucks, 1/2, 3/4 and some 1 ton trucks. This information is acording to "GMC, the first 100 years" by John Gunnell.
