How would I calculate, maybe you know the answer too how much these heads have been milled?

I know that stock chambers are 65cc chambers and every .007 you mill drops the chamber volume by 1 cc. The combustion chamber is an irregular shape so I have no idea how much of a volume increase the chamber undergoes by milling to accomidate a 4" bore. Getting to 62.88cc on a stock bore head would be done by decking .0148" I would appreciate any input so I can better plan the cam swap.

LS6 243 casting heads

I'm worried about piston to valve clearance issues running:

 

Could I use the LS2 head chamber volume since it is similar and accepts a 4" bore? Then I could figure out how much my LS6's have been decked at that point.

 

alot of people say every .005-.006 thou is a cc removed.

 

6-7cc is what many of us use.
I normally use 7 because I like more compression. So 35 thous milled would be 5 cc's.

 

How would that change what's actually taking place? I don't understand It should be exact conversion for the most part unless the LS series chambers are shaped differently

 

if you need it exactly what you want i'd say the best thing to do would be to cc them before any milling then .006 thou per cc will get you very,very close to your desired cc volume.

 

I'm definatly going to get them cc'd but I was hoping I'd have a close guestimate before taking the engine apart. The one thing I can't stand is waiting on parts while the vehicle sits. If I new for example that I'd need new pistons then I'd go ahead and order them before hand that way the engine comes apart and it goes back together as fast as i can work. None of this waiting around a couple of weeks for parts