Thanks John, but what does this quote by duxthe1 mean---"Yes the head will bolt but the 2.6 head has a squish pad and the 3.0 is an open hemispherical chamber. So a 3.0 head on a 2.6 would have a lot less compression. FWIW, there may be a few oddball assemblies out there but AFIK... no dice."
My head does not have a totally open hemispherical chamber.
Should there be clearance indents for valves on piston tops for 3.0 pistons? Pics would sure be nice. Anyone got pics? I will post some soon...........