Ok, the combustion chamber I refered to is in thecylinder head, where the intake and exhaust valves live. The US head has a slightly larger combustion chamber; other than that I think every thing else internally is exactly the same. IMHO the way to make the US engine run as fast as the UK counterpart, might lie in the ignition timing. Because of the higher comp. ratio the initial timing on the UK is **should** be a little further retarded than the US model, so if you bolted up the stock UK ECU this might explain why it is not quite as peppy as your mondeo motor. As to how much the timing would need to be advanced I don't have the foggiest idea, maybe Terry Haines could help you out there.
