The instruction manual notes that the center line is offset to the left side to accommodate for right thrust. There should also be 2 degrees of right thrust built into the firewall but on my model the thrust line was dead center and the firewall mounted square. To fix this I put 2 washers behind the motor mount on the left side and shifted visually the motor mount to allow the motor to exit through the center of the cowl. The pictures above show this in detail.
Thanks for the info! I measured my firewall and it is also square to the sides of the fuselage and the engine mount lines on the firewall were aslo dead center, not offset to the side.