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Im trying to figured out how much compression i will have. Ok its a 350 bored 40 over, speed pro flat top hypers with four valve reliefs, i will be using 64cc double humps, ok the book says 9.3 with 64cc heads. But my block was decked so the pistons are close to .008 in the hole. How much will that raise the compression? Also if i went with a .015 head gasket how much would that raise compression. My cam calls for 10.5 i didnt realize that until it was already installed lol. Thanks for help.
 

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bracketracer said:
Im trying to figured out how much compression i will have. Ok its a 350 bored 40 over, speed pro flat top hypers with four valve reliefs, i will be using 64cc double humps, ok the book says 9.3 with 64cc heads. But my block was decked so the pistons are close to .008 in the hole. How much will that raise the compression? Also if i went with a .015 head gasket how much would that raise compression. My cam calls for 10.5 i didnt realize that until it was already installed lol. Thanks for help.
There are a lot of calculators out there, however, this simply the ratio of volumes above the piston divided by all the volumes.

Volumes of cylinders are the area times the thickness. Area of a circle is .7854 times the diameter squared. For a .040 over 4 inch cylinder it's 4.040 times 4.040 times .7854 times 3.48 inch stroke yields the volume of the cylinder. The volume of the space above the piston crown to the deck is computed the same way, it's just the distance from crown to deck substitutes for stroke. The head gasket has a bore larger than the cylinder but is calculated the same. These calculations are usually done in English measure, to get them to cubic centimeters (CCs) multiply cubic inches by 16.4.

The volume of the piston dish or dome as well as the combustion chamber is given by fluid measurement.

Bogie
 
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