Reply to "Is this a 351 Cleveland?"

Its a 351W.

In a Pantera, one aspect of the engine most visible is the rear of the intake manifold, which must conform to the shape of the rear "valley rail" of the engine block. So perhaps the attached picture shall help you identify engines in the future.

Also notice where the rear of the intake manifold seals against the block, there is a gap between the manifold and the top edge of the bell housing. You can see about an inch of black engine block between the two castings. This is about the same for the 351C (9.2" deck height) and the 351W (9.5" deck height). But the little 302 (8.2" deck height) does not have a gap in that location, the top of the bell housing is flush with the rear of the intake manifold.

This engine is also equipped with in-line valve 302/351W style cylinder heads, the rear of the 351C cylinder heads are larger and rectangular in cross-section.