Can someone tell me the best way to find out where to drill holes on the firewall for the engine mounts. I have built several planes in the past but all have had the holes predrilled. The book says install motor. Period. This is a cap 232 with a YS FZ 91 4 stroke motor. The other little problem is that the distance from the firewall to the prop washer is 120mm. I do not have that much room because of the pump on the back of motor. I need about 8 to 10 mm more space. I guess the only problem might be the prop sticks out farther than it is supposed to and maybe the CG might be off some. Any Ideas.