Under magnification, the K75 engine is definitely a photoshop job, but certainly one worthy of 5th Avenue or Playboy. The Oilhead is curious, it is either an extraordinarily good photoshop job, or it is genuine.. I can't figure how they've attached the engine to the frame, though. On the oilhead "frame", it would be attached from above and towards the front at the big Y-arm for the telelever. How they managed to hide that all so well underneath that R60 or /2 tank - and strengthened the upper part of the frame to take the load, I don't know.
Metallurgical wizadry, indeed !