Noticed a lot of misinformation in this thread. For instance, the 9N tractor engine was in no way connected to the Model A/B engine! It was basically half of the '39 Mercury V8. Pistons, rings, valves and lifters are absolutely identical and interchangeable. The oil pump is very similar to the V8 60 pump (the gears may be the same). The distributor was mounted on the timing cover and driven directly from the cam. It had insert rod and main bearings and was full pressure oiled. The starter was from the V8 60 also. It was not used in the Jeep, but was available in '41 and '42 pickups where it was rated at 40 HP, I believe.
Get a load of this: According to the book "The Fords in My Past" by Harold Brock (chief engineer of tractor engineering from 1939 to 1959 at Ford and main designer of the 9N,): "Ford designed and built the first prototype" Jeep. And, copies of Ford's drawings "were transferred to Willys as a second source".
The original Jeep patents (nos. 2,317,619; 2,317,620 and 2,319,869) "were issued to C. F. Kramer of Ford Body Engineering Department".After the war Willys-Overland was charged with false and misleading advertising by the Federal Trade Commission for claiming to have designed the Jeep and it was proved in court that Ford drawings were copied and used by Willys. A cease and desist order was issued by the Federal Court for Willys to stop "claiming to have designed this vehicle". So Jeep DID NOT write the book after all!!