Canadian engines for some years in the 48-54 era used aluminum versions of the stock intake manifolds. I have one, paid about $75 for it as I recall. They weigh about 100 lbs less than the cast iron ones (not really but it feels like it). They also used cast aluminum timing covers, but those aren't necessarily a direct bolt on.

You "can" use a 38-48 car/truck intake manifold on an 8BA, but you lose the improved crankcase ventilation of the 8BA style manifold, and have to make some easy internal changes (removing a stovepipe that is under the manifold). You'd also have to use the early-style fuel pump stand and probably the pump itself, and use an early style pushrod.

It sounds like you are looking at a Canadian C8BA manifold; it's easy to tell as it will have casting marks "C8BA" or "C8RT" in plain view.