The Willys F4-134 Hurricane was an inline-4 piston engine and powered the famous Jeep CJ in the CJ-3B, CJ-5, and CJ-6 models. It was also used in the Willys 473 and 475 pickups, wagons, and sedan deliveries. It replaced the Willys L-Head engine which was used in the Military Jeep .
The Hurricane is one of the few "F-Head" engines, and the only one well-known. The "F" comes from having one set of valves in the block, like a flat("L")head, and one set in the head, like a modern OHV engine. The reason Willys did this was because they used the L-head block and modified it to have the intake valves in the new, much taller head. This created a very compact combustion chamber and a high compression ratio, boosting power.
The F4-134 was introduced in 1950 in the new 473 trucks. However, it was not placed in a CJ until the introduction of the CJ-3B in 1953, which had a distinctive high hood to accommodate the much taller engine. The engine remained in production until 1971, after Kaiser Jeep was purchased by American Motors.
