Direct answer: Yes. Inlet and outlet size is set at the drawing stage, so a part can be built to the two sizes the buyer specifies rather than to a catalogue size. Catalogue examples are the Custom Water to Air Intercooler, the Custom Titanium 4 inch Short Ram Air Intake Kit and the CUSTOM SIZE SS304 clamps.
Size has to be decided early because the connection is formed, not adapted. A formed hose, a welded pipe and an intercooler end tank each take their shape from a fixture, so changing a connection after the fixture exists means changing the fixture. The buyer supplies the inlet size, the outlet size and the hose or pipe that will join them, and the part is drawn around those three facts.
The same logic covers the wear ring listings, which are offered in more than one fixed size, and the clamp listings, which are made to the size on the order. What is not offered is a size guessed from a model name: two hulls of one family can take different connections, so the measurement comes from the buyer's own part.
