Here's where a 351C differs from the garden-variety small-block Ford. Coolant never enters the intake manifold because the 351C has a dry manifold. At the upper righthand corner of the 351C head gasket is a coolant passage that carries coolant to the thermostat. The same is true on the other side. Be careful because you can install the 351C head gasket backwards and experience overheating. The little square passages go at the front--and "front" means front.