I just looked at a pic on Warmonger's site that shows combustion chamber on the 2.5 Duratec head, and it still looks like it has quench area to me? Correct me if I'm wrong, but I count 2. One on each end of the combustion chamber. The total area of this is just as big as the quench area that the 30 year 'old' small blocks have. The laws of physics don't change (to the best of my knowledge). Quench is still good to having a more efficient engine. Breathing is a key too, but the main reason these engines have 4 valves is to provide a wider usable powerband (w/ the tuned primary and secondary runners and cam profiles). Many racecars using a tuned-in but narrower powerband still have your good ol 2 valve setup, since they only run at a certain rpm range for the race. He can do what he wants, but you wont see me putting a thicker head gasket on my engine when I do the 3.0 swap (if I do it). I would rather open up the combustion chamber a little, or get the lower CR pistons as a preference.
