I just finished my sukhoi. I had the same thought as you when I looked at the hole in the firewall, but I think it is just an illusion. The hole does look low because of the cut out for the muffler, but once my engine was mounted the cowl centered up very nicely with the spinner. I basically just went by the picture in the manual with the engine (2 stroke) mounted 45 degrees inverted with the muffler in the factory cut out.