Hi,

Is it possible to rotate the engine slightly? So long as the thrust line doesn't change it doesn't matter to the aircraft if the motor is vertical, inverted, on its' side or any where in between. Rotating just enough so the old holes don't come into play with the new mounting bolt holes is one option. Often with a four stroke to get the muffler to exit the bottom of the cowl the head is roughly at 7 o'clock when viewed head on.

Or have you already cut the cowl?

Good Luck,

Colin