Yeah, I see that the nose of the gear box protrudes, but those shots of the models look like it protrudes too much. If you take a line from where the prop shaft emerges from the reduction gear housing (on the 'green' model), and extend it outwards parrallel to the front edge of the cowling, it appears to be far too far forward. As I said earlier, I hope I'm wrong. But, if I'm right, I'd suggest looking at ways of either shortening the engine mounts, or maybe reducing the depth of the rear cylinder bank or similar, in order to stop the whole lot being too far forward. A bit (a lot!) of trial fitting before committing to that part of the build should find a solution.