Good afternoon gentlemen just joined your forum. Looks to be filled with many knowledgeable people.

My question is: Im am just going to start delving into giant scale aircraft & I know very little about gas engines.
I'm going to be building A Top Flite P51 D giant scale and I need to know what size engine will work well in it?

I always went 2 sizes larger in my smaller airplanes and that always worked great, but with the gas engines I have no idea where
to start .

So any info you could provide would be greatly appreciated.

thank you
Robert