Hoping not to throw wood to the flames, I'll add that OS makes nice aluminum mounts albeit a tad expensive. The 905 mount fits a wide range of OS engines in the 60 to 90 displacement either two or four stroke as well as all the Rossi and NovaRossi two strokes in the same displacement class. Basically the mount has a 25 mm bolt spacing on the lug which matches a number of pattern engines with the other set of engines having a 20 mm spacing (e.g., YS, Enya, Webra, etc) - these engines don't fit.

The mount itself can then be either hard or soft mounted... ;-)

David