I have a .40 mounted inverted in a Sig Rascal 40. I had to remove the cylinder, (cooling fin part only) and exhaust collector ring, bolt the crankcase into the plane and then re-assemble. It turns a 12x6 three blade at 8,300 and seems to be the perfect powerplant for the Rascal. Everbody loves the neat sound of the exhaust, it has a deep authoritative sound for a .40, no whine or bark.