Billet head shell for the Yamaha 701/760 that allows the use of our Sea Doo 951 domes. This is for building a custom big bore engine that is larger than 86mm bore size. You can also have custom domes made if the standard 951 dome configuration will not work for your application. Custom domes start at $80 for programming plus the price of the dome. Includes the orings and brass water fittings that go in the head shell. Domes NOT included.