The 71 series engine was first introduced by GM in 1938. The “71” designates 71 cubic inches per cylinder. Therefore the 3-71 used in the Oliver Super 99, 990, 995 and also the Oliver built Massey 98, has 213 cubic inches.
In 1955 Oliver began incorporating the 3-71 GM engine into the powerful Super 99 tractor. The company needed a more powerful engine than the 6-cylinder, 195 Waukesha in order to provide its customer with a big horse. Because of the unique and adaptable design of the 71 series engine, it can be used in many different applications and configurations while keeping parts inventory to a minimum. Oliver personnel at that time consisted of Chairman of the Board, Alva Phelps, who came to Oliver from GM. Oliver had the contacts at GM and the 3-71 was a proven engine that was well suited for the application.
In the Oliver 990 tractor application, the 71 series was rated at 81 horsepower on the drawbar and 88 on the belt. Today, Oliver tractors that use the 3-71 engine are the most highly sought after in the collecting world and also in the pulling world. If you are looking to purchase a GM-powered Oliver, it is wise to thoroughly inspect the engine to see exactly what you are looking at. These tractors are 50 years old and they have been used. We don’t always know what bandage fix some farmer has used through the years.
Read the entire story along with great illustrations to help identify your 71engine in Issue #30.