Mark, If you have to make two saw cuts (on each beam), one horizontal one vertical that intersect, don't just cut untill the two saw cuts meet. This will create a weak spot as the cuts will most likely over lap each other a little. Instead drill a hole (3/8"-1/4") where the intersection will be and carefully saw each cut to the hole leaving a nice rounded transition from each angle. File and sand smooth the area where the saw cuts were made and you will have a strong professional looking modification to your motor mount. If you don' have to remove enough material to need saw cuts, then just file the area with a half round or rat tail file, and sand smooth.