Safe ratio = 9.0-1 iron, 10-1 aluminum.
More than a average size camshaft? 244 - 255, @ .050 Add .5 - .75
Big camshaft? 260+ duration @ .050? Add 1.0 +
Keep in mind the Dodge NACAR truck effort used cubic inch limited engine limited to 9.0-1. The made over 600 HP. Compression is often over rated and most mis used issue. It is best to have excellent air flow in and out of the engine than it is to have a high compression ratio. On a street car, to much ratio limits your cam selection while being limited to pump gas.