The Chevy and GMC sixes were differant over the years, but merged when Chevy came out with the seven bearing 194/230/250/292 series in 1963.
GMC had the 228,248,270, and 302 in pickup trucks, and there were bigger GMC sixes for larger chassis.
Chevy's 216 came out in the late 1930's, and there was a 235 based on the same engine. This engine had dipper lubrication to the rods.
The 1950's saw the development of the full pressure 235 in 1953 and the larger cousin, the 261, which shares much of the same internals (crankshaft, water and oil pump, manifolds) as the 235.
The GMC engines are generally better than the Chevy engines of the same period but don't bolt directly in. They are also more expensive to rebuild since parts are more scarce. If you have a car/truck with a 235 a 261 will bolt right in its place. 261's can be found in 2 ton and up Chevy trucks and busses from 1955 to 1962. They can also be found in Canadian Pontiac cars, but without the full flow oil filtration that only the US 261's have from '57-'62. They can be told apart by the presence of large 1/2" NPT oil lines going to a big cannister filter on the intake manifold.
Visit
www.inliners.org for more information and lists of casting numbers. Welcome to the Stovebolt board!
