The engine is a 351C, I see a few confuse the I beam shaped manifolds as Magnum manifolds.
Small port V6 engines also used I beam shaped manifolds and if you look at the collector it's extremely smaller from the Magnum manifold. There are 4 different styles of Magnum manifolds!! The governor on the carburetor is the velocity type used on many 305 engines including pickups as well as 351C engines. Magnum engines used the spinner type fed from the oil pump. The carburetor is a ww 2 bbl also used on 351C engines. All Magnum engines as well as the non Magnum 401 & 478 engines used the larger WWC 2 bbl carb.