Getting the compression ratio and plug right is the key to geting more power with more nitro.

You need a lower CR with more nitro and may need a cooler plug.

Add a head shim and play with different plugs. Guesstimate your airborne RPM and ground run with a smaller prop to achieve that RPM

You will not get massive increases 100 - 200 rpm. If anybody tells you they got 1000s then get the salt cellar out.