If the Catalina 270 is equipped with a Perkins P-20 engine, it sometimes has a 2" exhaust. If that is true for your boat, it will be necessary to order the 2" Insert Elbow located below under "May we also suggest". The two different elbows are interchangeable in the muffler and allow use of either 2" or 1-5/8" inlet hose.

To the best of our knowledge, the outlet hose remains 1-5/8" regardless.