I have searched for info on the cc for stock 340 X,J,O and U 2.02 heads and have found answers from 67cc to 72cc so I don't know what to believe. I'm sure the head gasket thickness will affect this too but I am trying to get an idea about what compression I will end up with by uning the Diamond pistons I have. I have several sets of 2.02 heads and did not know if one would be different from the other.

If they have not been milled any. They should be very close to 72cc. Jim

To get the results you want you should CC every chamber in each head until you get two heads with the CC you want to start with I've seen 4.3 CC diffferences bewteen chambers on the same head on wedge and 426 Street Hemi heads

When I had the machine shop check the cc of my x heads they were 74 cc. These were stock untouched heads. This was back in '95. Maybe the valves were sunken a little I don't know.

Speedway motors has a CC kit for real cheap. Can slightly deburr the chambers till they're equal (to the largest one of course) then mill em as needed keeping in mind SCR/vp clearance. Best would be to also mill the open chamber areas (get em flat/same depth) then get .040" piston/head quench. $$$ but worth it if set on using OE open chambered iron heads. Unshrouding at the outer end of the intake/ex valves to add the CC's works the best for flow.