Over the weekend I've tried to educate myself a bit better about compression ratio and how to calculate it. Based on the information that I have been able to gather on these Sealed Power 310P pistons that I put in my 327Q I've come up with the following:
The head volume is estimated (I knocked .5 cc off of the stock nominal value to account for the re-machining of the heads), the "eyebrow" volume is estimated based on figures available from Summit for similar pistons, and the deck height was measured.
The stock compression ratio was 8.8:1, and with the modifications that have been a slight increase is expected. Do you guys think that by retarding the ignition I can run regular or mid grade gasoline in this engine? If I switched to 13 cc dished pistons I could get down to 8.29:1 or so, it would be inconvenient to do, but it would be much worse if I decided it was necessary later on into the build. Just not sure if I am so far off from stock that it is worth the extra time/money.
Derek