Ahah it all becomes clearer now. I should have mentioned that the engine is now setting in a 1946 1 1/2 ton truck. So I have to asume that at least the manifold on the 1946 engine is the original? But I thought the other one was original also. Maybe they changed the design of the shape of the manifold and how it bolted on between the years of 1942 and 1946. Does any one have a 1942 engine with the original manifold on it? Does it have the ears on the manifold on the bolting surface of the bolt one in from the outside bolt? It also has a place for an oil filter to bolt on using clamps in front of the carb. I think I will use the 1946 manifold. I tried both manifolds on the engine and both line up perfectly with the ports,same size by the way, and bolt holes.