Hi, I have a Mk6 Fiesta with a 1.25 Duratec has anyone changed the cylinder head to one off the 1.4 duratec? Or know if doing it is possible? Many thanks

I'd have thought they would have different sizes bores due to the different displacements?

I see, but as a way a way of upping the displacement a little bit

It simply wouldn't line up with the bore of the engine block, hence you'd probably strip the piston rings off or loose compression altogether. Better off increasing the stroke of the engine. That way if you had an accident and the insurance company were suspicious and they very unlikely decided to measure the pistons they'd still be the correct size.

Or buy a used 1.4 engine (I have one for sale ;) )

I dont understand the above questions and answers.Changing heads will not increase the engines cc,but might change the comp ratio or cause the valves to hit the piston.Years ago we used to swap the heads off different crossflow engines in the belief we would get more power ie 1600 head onto a 1300.If you lengthen the stroke on the standard block you will send the pistons straight into the cylinder head not "not strip the piston rings off".If the 1.25 and the 1.4 use the same head casting but with different valve sizes as long as the valve lift is the same it should fit but i would think lots more parts would need to be changed as well.

The stroke is the same the bore is the difference, 1.25 is 71.9, 1.4 is 76, not sure if it works but the head gasket may not seal correctly.