1975 International 200 Series Pickup

Hello, I have a 1975 International 200 Pickup that is supposed to be a 345ci automatic V8 with 13689 miles. I am having trouble finding parts, specifically an exhaust manifold. The manifold is supposed to be a center dump according to all I know about a 345. The engine in the truck now is a V8, but the exhaust manifold has a rear dump. My question is can someone please inform me of how I can indentify the engine.

Thank you