Determining Compression Ratio

[LingLing]

I know, I know. Subaru tech on a Mitsubishi site, but the math is all the same.

Since I didn't put the motor together and it's a hodge-podge of various oem parts I don't know the exact CR. So I did a bunch of looking and here's what I came up with.

-EJ22T block (Stock bore)
-Stock EJ22T pistons
-Stock STi rods
-Stock EJ22T crank
-EJ25 heads
-OEM Subaru headgasket

Using these numbers..

Cylinder Bore: 96.9mm
Stroke: 75mm
Head C.C. Volume: 47cc (I couldn't find a definitive answer, since I don't know what year heads are being used. I tried to choose something realistic)
Headgasket Bore: 97.5
Headgasket Thickness: .59mm (Assuming they used an oem EJ22T HG)
Piston Dish Volume: 28cc
Piston Deck Height: 0.016" (Again, I chose to use this because I couldn't find a definitive number)

I get a CR of 7.98:1

Now, what's tough is I don't know if they used a head gasket from an EJ22T or an EJ25. Difference in bore makes is approx. 2.5mm-3.5mm. Enough to skew the result.