Originally Posted by Matt J

So in a round-a-bout way Euan you've ended up saying the same as karl?

Those OHC examples you gave, if its the same head etc on them all then its obvious that the heads nowhere near its flow limit, so all ford did was swap the bottom ends and fit a different carb (assuming the carbs are different) this would give the increase would it not?

In which case it wasnt really the capacity change that increased power it was the that the head could flow enough power in the first place.

I'm sure if the head was designed for max flow on the smallest capacity engine the power wouldnt go up if you bolted on the biggest capacity bottom end would it?