The bolt spacing on the rochester is wider. The engine might not be original. It is definatly splash oil, but it could be a 216 or a 235. Did they have different intake manifolds between the two engines.

1937 Chevy 1/2-Ton Pickup x3
1940 Chevy 1/2-Ton Pickup
1940 Chevy 1 1/2-Ton COE
1941 Chevy 1/2-Ton Pickup
1941 Chevy 1 1/2-Ton COE
1941 Chevy 1/2-Ton Suburban
1946 Chevy 1 1/2-Ton COE
1971 Chevy 1/2-Ton Pickup
In the Stovebolt Gallery