making some changes...need cam advice

[hobgoblin351]

If the advertised comp ratio of the pistons you are running with the 60cc chamber is 10-1, in reality it will probably be lower. The larger the cam the more compression you'll need. Hey Rev those are good number with that setup. If he's running that you can to and still be streetable.
To calculate comp ratio:
Swept volume+ chamber volume
Comp ratio= ----------------------------------------
Chamber volume

Swept vol- is the capacity of the piston. The stroke x the volume of the bore

chamber volume-the vol of the combustion chamber+ the volume of the compressed gasket+ any valve reliefs+ The volume lost from deck clearence+ the are between the piston and bore down to the top piston ring

Now the swept vol is easy, the vol of the chamber,compressed gasket, and valve reliefs are all given too. (if you're running a dished piston subtract the volume of the dish) You can guesstimate the volume lost from deck clearence and around the piston. Take the deck height x the volume of the bore, that should get you close enough. Add 1 or 2 cc's for the area around the piston above the rings if you want. The thing is most advertised comp ratios on pistons dont use the gasket volume or the deck clearence in their calculations. Surprisingly your comp ratio could be lower than you think.