I doubt that you'll reach 100 mph with a prop having 5" of pitch. I haven't done the math, but I really doubt it.

On the other hand, if you want to go really fast with that model, drop down to a 9x8 or 9x9 prop, remove the landing gear and tune up the pipe to match the load.

You will probably have to add a gasket under the cylinder head to prevent pre-ignition. This is typical when using tuned pipes OR you could drop down in nitro to say 5% or so.

Have fun.

Yes, we are all nuts.