Being new to this.  I was thinking of cutting the shaft off where it exits the rear of my motor, (It stuck out about an inch),  so I wouldn't have to cut a hole through the firewall for it.  It then dawned on me I could use it to center my motor, and mark the holes for my mount.  All I had to do was mark the center line of the firewall,  then the horizontal thrust line.  I then drilled a hole the same size as my shaft where the two lines met, and inserted the rear shaft, (cut to leave 1/4") of the motor with the mount installed into the hole.  I then just eyeballed the mount, and marked the bolt holes with a Sharpie.  When drilling the bolt holes, I also drilled the shaft hole bigger so the shaft wouldn't rub on the firewall.  

Thought I would pass this on.  Probably old news for a lot of you, but hopefully I can save someone some grief.


Gonzo