2.25 vs 2.5 Cylinder Head

[sven]

I have a 2.5 petrol with low compression issues...still have to do a leakdown test to confirm head or low end. I also have a 2.25 petrol engine with a good head. Are the heads interchangeable between the 2.5 and 2.25? What about the valves/guides/head gasket, etc.....are teh rebuild parts the same?

[yorker]

The 2.5 will have metric fittings IIRC that was the only difference. I think Discotech in Canada was selling complete unleaded 2.5 heads for $500 a little while back.