I'm going on a limb and saying they're the stock Pistons. IF being so yes the Compression was 8:1, or 7.9:1 ish. So whats the next step then to increase compression. I heard this as well before but, again I'm learning as I go so any help will be much MUCH appreciated. Noted you said Pistons with POP-up, what else would be needed with this, or just for the time getting the compression right to hopefully get a bit more GO.