compression question?

[fastfox90]

picked up a set of gt-40 heads for a good price. Any one know how badly they will drop my comp. ratio from the e7's? not wanting to put alot of money into these heads, but do I need to have them milled? most cams im looking at want a minum of 9 to 1, not sure what it is stock, but will the heads kill the ratio??? Thanks for any advice

 

[Rick 91GT]

It will be between 64-60cc just like the E7, I have found they are not that consistant.