[steelcomp]

In my experience, it's not a really reliable source to refer to the mfgr's numbers. Case in point. (Bear with the treasonous example, here) BBChev...TRW pistons "advertised" with a 119 cc chamber, and a given dome volume, as a 12.5:1 CR piston. I was looking for max compression without angle milling, or any other exotic techniques. I went to zero deck, and surfaced the heads (after polishing and cc'ing the chambers) back to 118.8-119 cc's. When I did a cyl pour to actually measure the piston dome, and calc'd the CR, it was 11.2:1. So now, when I see the TRW's advertised at 12.5:1, or someone tells me that they have "12 1/2 to one cr" in their BB Chev, I know better.
You won't know untill you measure, or you talk to someone with the exact set up who has. To me, when buildiing a motor, this is preliminary. Gioin strictly by mfg'r specs, even as a base line, has been proven unreliable.

Just my $.02