In the prototype development stage, it was originally an air-cooled single-cylinder, borrowing from their current motorcycle products, but a V-twin engine proved more practical. To aid in cooling, a forced air cooling system used a propeller fan to further direct airflow across the cylinders without an encased cooling shroud, and it used a dry sump oil lubrication design. The carburetor was copied from a Wheeler-Schebler Carburetor Company design in a single barrel carburetor that was placed in the center behind the V-bank, distributing to the left and right cylinder bank, through a cross-flow cylinder head. The engine was suspended above the front wheel differential and in front of the transmission. This arrangement gave the vehicle a higher center of gravity, helping to keep the engine out of river crossing conditions, with the disadvantage of higher engine vibration than a horizontally-opposed engine layout. This trade-off meet the primary goals set before the development team. Manufacturing was simple thanks to the symmetrical implementation with the engine directly in front of the transmission, with a transfer case providing power to the front wheels installed directly below the engine. Because assembly was almost by hand, minor changes were made to various aspects of the car as the need arose, with the early prototype two-door enclosed sedan evolving into a roadster. While some vehicles over time had body changes, many of the production cars were not installed with doors, and the canvas roof for the two-door and four-door vehicles aided in reducing overall weight and adding flexibility to conditions in the field.