Pistons specs question for 340 build

448Scamp said

That’s because TRW plays fast and loose with dome volumes. Those pistons are about a 6-7 CC dome when you subtract the valve notches. That’s why guys have much lower compression ratios than they think because they don’t measure the actual dome volume.

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I'll tell you something else. Hardly anyone EVER includes the correct chamber volume, either. How you ask? Unless you do a .500" down fill of the cylinder, you don't know what you have. You must do that to include everything above the top ring. Most people leave that area out and it can be pretty big, especially with pistons like the KB hypers, with the top rings further down than a standard piston. Without the area from the top of the top ring to the piston top added in, your calculations will not be correct.