Raises the height of the GM V-6 & V-8 small block (non-Electronic Control) engines with dry joint exhaust system to prevent water from entering the engine through the exhaust system. Maximum height of 6 inches (152 mm). 3 inches (76 mm) for CLOSED COLLING and dry joint exhaust manifolds. Fits the following models: 2004 - 2016 MerCruiser Marine V-6 & V-8 (305, 350, 377 cubic inch displacement) non-Electronic Control engines (serial number 0W310000 and up) 2002 - 2016 MerCruiser Inboard V-8 (350, 377 cubic inch displacement) non-Electronic Control engines (serial number 0M390000 and up)