Great explanation Wingracer!

The engine-mfg has in 9/10 times done the their best to suit as many owners as possible. So in 9/10 times there is little to be gained without the lose of something else.
Today with good CNC-machines the engines are also closer in tolerances, so they donīt add as much of a safety margin to them.

But if you have an interest in trying and to learn, go for it!
But as always, you should begin with knowing what you have and make plans to were you want to take your engine.

A couple of tips, if you ask me... If you do want a broad power curve, run large squish area and try to gain as much in the geometry of the chamber as possible without changing compression or squish velocity to much.

And I do a apologize that Iīm not as good as Wingracer to explain things!