I have a model of an engine's intake port. This is a solid model of the airspace in the port (not the walls around the port), as if you had poured foam-rubber into the port, let it solidify, and then pulled it out; it is the shape you would use as part of a casting core. The part is modelled mostly as a lofted boss, composed of maybe half a dozen cross sections at a variety of non-orthogonal orientations.
I want to create a model of the whole cylinder head. Rather than tediously recreating each of those cross sections in the cylinder head model and then making a lofted cut, is there an easy way that I can put the two parts in an assembly, and then subtract the port model from the head model to create a hollow intake port?