ORIGINAL: Shrky
As for power I'm not sure, I see a lot of G-62s in 1/3 scale WWI warbirds but I can't imagine needing that much power.
I would love to follow your build. I have the BUSA 1/4 version, looking forward to building it, but will be a while. Maybe I can unabashedly "steal" your ideas
As for the huge chunk of engine on the 1/3 scalers, there's three reasons I can think of.
One is balancing weight. If you are going to have to add weight to make the short nose balance, it might as well be useful, and not a bunch of lead.
Two is to be able to swing a scale diameter prop (or close to it) at a slower engine speed. The reduction drive mentioned above would do that also, but there is still the balance issue, plus the reduction drive is more complex than a lot of modelers want to mess with.
Three is that there's a lot of drag going on here, that big engine will come in handy. Sort of goes along with #2.
Keep the build thread going. It's going to be a nice plane.