It won't matter. There are no actual rules on where the engine thrust line has to be relative to the datum line or the wings or tail. The plane's designer figured out what worked best on that particular airframe, but even then a move of 1/4 inch up or down isn't going to make any difference. Are you thinking of moving it up or down for clearance reasons? The really important thing is the thrust angle, which may change since you'll be swinging a prop that's so much bigger.