RE: Norvel's A6R AME .061 R/C vs similar sized engine
The .061 AME is designed for small props and high RPM usage. It will not make you happy on a large of slow flying model. We are told that the AME is less friendly to tune, I didn't really notice any real difference. The .074 is in a different ballpark. It is able to swing larger props or small props quite fast. It is more friendly to operate and tune. The muffler bolts on and is less messy.
Norvel .074 all the way..