Look carefully. Like the new Street, each cylinder has it's cam chain and spark plug on opposite sides. The rear head is just the front head rotated 180 degrees. It is a 60 degree SOHC V-Twin like the Street with the final drive on the left. Even the wheels are of the same general style. The biggest difference is the 1100 OHC prototypes were air cooled.
Some will say an engineer left Harley on less than amicable terms and brought this design and that of the Nova V-4 to his new employer, Yamaha, where they became the Virago and V-Max respectively. This prototype considerably predates the Virago and the resemblance is apparent, right down to which side of the head each cylinder's cams are driven from, plug locations and the mounting of the starter.
I live in a parallel universe but have a vacation home in reality.