In the earlier years of engine development it was common for the rear cylinder to over heat and wear out quicker than the others along with very Poor fuel economy. John Bennett developed a Water by Pass System and much improved water pump for various makes and models to retrofit. John is an ace engine builder and few people know engines as well as he does. Today many of the manufacturers are using the water by pass system in various manifestations but to get the full story you can order the DVD from Nutech2000 at email@example.com. $20 will get you the DVD lecture by Darryl O’Bryan who worked with John for many years. You will learn a lot about engines that is often over looked.