I have a Saito 150 mounted inverted in a Tiger Moth. The ONLY problem I've had is flooding due to the tank being higher than the carb. I've since cured this problem.

Running? Runs great, excellent throttle response, idles reliably between 1900-2100, even with slightly rich idle mixture on a 15-10 prop.

Don't worry about it... The big Saitos are great motors in any position.

Dave