Heres a link to a recent thread concerning this topic, GOOD stuff.
So how much dynamic compression are you guys getting away with on street pump gas?
From the calculations it looks like I'm running 7.9
Gessford spec'd out the custom piston for CC of the "dished top" and compression height based on block deck height, rod length etc. The cam profile was to work with the final compression ratio of my iron high riser heads (9.8 to 1) and my final drive ratio. As the motor runs excellent on pump gas and makes plenty of power (11 sec range in the 1/4) I'd say he "nailed it"!