I am constructing the P-51D Double Trouble. I am getting ready to mount the engine and noticed that the marks placed by the company on the firewall (that I ASSUME is the center point and thrust line) appear to be off center by nearly 3/16th. In the picture below the mark through the center is mine and the factory marks are to the right. I am assuming there is a reason that they are off center but with no directions I question the location. It appears that it is setup for a Horizontal (side) mounted engine because the supplied engine mounts do not fit between the triangle stock on the firewall for vertical mounting. When holding the mounts in the horizontal position everything lines up. I am mounting my engine inverted with an incowl exhaust! I do not under stand why anyone would mount an engine horizontal on a P-51. Any help is greatly appreciated. This is the first time I have built one of these SEMI BUILT KITS (not an ARF by any stretch) with little to no directions. Thanks Skip