If someone were to design the ultimate engine mount system for mounting an engine to a square tube,
the criteria list might look something like this:
Strong: 6061 T6
Versatile: Can Do Straight Mount, 2 deg. Left or 2 deg Right; 2 deg Up or 2 deg down
Adaptable: 277, 377, 447, 503, 532, 582 Model 90 or 582 Model 99 and 618
Easy to install: Pre-Drilled mounting holes on 1" centers.
Allow access to engine bolts
This engine mount, just might match that criteria. Part nomenclature: 2" Square Boom Tube Mounts (Left and Right)
Rotax 2 deg Angle Engine Mount Bars (Front and Rear) Flip both over for opposite angle.
00BARRY MOUNT 22001-12 YLW/WHT MED Available at Aircraft Spruce