The 351C block offers excellent bottom-end support and can take high revs without breaking a sweat. This makes it stronger than a 351W block. The downside is an oiling system that's inadequate, as it comes from the factory. Cam bearings and lifters get oil before the mains, which causes oil starvation issues under extreme conditions. Experienced Cleveland builders opt for all kinds of oiling system mods, including an external oil line from the front of the block to the rear to improve oil flow at the mains. A restrictor kit is also available from Moroso.