Investigate the M111, M104, M119, and M120.
These are the Mercedes Benz 4cy, I6, V8, and V12. They use practically the same dimensions for everything (rods, throws, etc.) Even the cams use similar duration. You can compare hp/Liter at your own will, though using the 500e M119 would be a joke unless you compared it with the Kompressor M111, C36 M104, and AMG (7.3) M120, since it was built and tested by Porsche