How much is "some" MMO?
My guess: no more than 50% of the chamber volume (never the cylinder volume). If you added the full chamber volume the CR would be infinite: breaking things.
Chamber volume = cylinder volume ÷ (static CR - 1)
For a 235 @ 8.0:1 CR
39.25" ÷ 7 = 5.6" or 92cc; add 2.8" or 46cc.
