Larger engine…Yes, there generally isn't a good substitute for displacement. While technically high nitro fuel will deliver more power, a lot is dependent upon the engine design. Most sport engines found in the states are designed for nitro in the 5%-15% range. Running a high nitro mix (like 30%) in sport engines often does not produce the desired results. On the other hand, a high performance engine that feeds on high nitro often will run like crap on 15%. Got to match the fuel to the engine.

I’d like to amplify on what bruce88123 touched on, power doesn’t do any good unless you can get that power delivered to the prop. Prop selection alone can often totally change a plane’s performance. I've seen a few who get larger engines only to be disappointed in the performance do to poor prop selection.

Cheers.