[Hotfingrs]

Ernie is right about the reasons for doing the above mentioned. Cylinder pressure doesn't tell you compression ratio, it only tells you the condition of the engine. As an example my engine is 10.5-1 compression. Last year I had 285 lbs of cranking pressure, this year I changed the cam and my cranking pressure is now 185 lbs, with the same CR. The cam was the only change made.