My edge with the fox weights in @ 15# dry, the fox weights 3.5 without ignition & muffler, so to answer you question yes the brison will work but it will increase the wing loading & make the plane a little more difficult to fly than if it had a saito 180 in it. But it is still managable & it will 3d fairly well. I found that most of the people here will tell you not to do it, I talked to "striker" in canada & he gave me a few tips on checking incidences & beefing up the firewall, I went ahead with it as I already had the fox & I am very happy with the outcome as I think you will be. If you are a pertty good pilot you shouldn't have any problem.
Good luck
Gil

Ps. there are 448 grams to the pound, 28 grams to the oz. & 16 oz. to the pound, the saito weights right @ 2 pounds