Calculating compression ratio

[exilous]

Hey so I am almost done with my engine build well the heads I snagged off another engine are worn beyond repair and my original heads don't have hardened seats so it would cost to much to rebuild those as well. I'm going to be picking up a set of aluminum heads and I tried calulating my CR before with my old heads and it kept coming out wrong. But now I need to recalculate for my new heads. So I did a search and came up with a range of answers. I want to run pump gas in it so I want to keep the CR as high as I can so I can still run 87 at the pump. Just as an example when I typed everythign into the calculator sites I went to I used 64 CC chamber heads as an example and I got a range from 9.43CR all the way up to 11.02. All i need is heads so I am open to different chamber sizes. And as for a head gasket size whatever came in my felpro gasket kit I didnt see a specific size or compressed thickness on the box anywhere so I dont know what size that is.

Another question while I am on the subject, I am getting news heads should I reuse the slotck rocker arms or should I upgrade to roller tip rockers or full roller rockers? is there a benefit? And should I stay with the stock 1.5 ratio or move to 1.6?

Thanks for all your help guys.

[HAULIN IT]

There are several things you need to know to accurately figure the compression of your engine...The CC's of the heads, the head gasket compressed hight,  bore size, stroke, piston to deck surface hight, dish/valve reliefs/dome of the piston. Can you explain what you were doing to come up with the differences in the numbers? You had to be changing some numbers or doing the calculator wrong. Lorne

[VileZambonie]

I usually bring the piston to TDC and level the engine on a stand. Then I take ATF if in a syringe graduated in CC's and fill it up until it's level. There's the area above the piston. Do the same with the combustion chamber with the correct spark plug installed. There's your combustion chamber volume. Keep in mind the Felpro gasket is not a perfect circle. They're usually around .040" compressed I believe. What do you have for piston's? Did you have the deck surface machined?