Oh, here's why.
Stock E7TE. 64cc
TRW Flat top piston with valve relief. Valve relief = 5.5cc.
Total combustion chamber size 64+5.5 = 69.5cc
4.030"x3.00" = 306ci.
Cylinder volume = (pi)(r^2)(h)
pi = 3.14159265359
r = 4.030/2 = 2.015 x 2.54 = 5.1181cm
h = 3.00" x 2.54 = 7.62cm
(3.14159265359)(5.1181^2)(7.62) = 627.08cc
Now take cylinder volume divided by total combustion chamber size.
627.08cc / 69.5cc = 9.02. That's your CR.
If you really want to get technical, stock CR would be 8.89:1
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