Carey, congratulations on flying the SD. I have a Brison 6.4 on my Lanier Extra 300S and I know how well it runs. There is no way that I can imagine that this engine will hurt the air frame unless you put it in a dive at full power. If you built it close to the plans and I'm sure you did, it will hold together well.

As I'm sure you recall, I fly a 1/3 scale Hostetler Super Decathlon and it weighs about 31#. My engine is a ZDZ80RV turning a Bambula 26x10 at about 5800. I quiet often fly the plane at full throttle doing loops and Cuban 8s. Sometimes I throttle back coming out of a loop and sometimes I don't. Not saying the air frame will never break but mine has been thoroughly tested with no problems.

I think you will really like the power once you get used to it. Of course, you have to use that power in the right way. That's what the throttle is for.

Ken