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PKRWUD · 07-17-2002, 05:19 PM

4 notches means the same piston can be used in any cylinder.

The formula is as follows:

Cylinder volume for a 302 is 617.78cc.
The space above the top ring, and the space for the 4 notches, is 5.5cc.
The average head gasket has a crushed thickness of .047", which equals 9.68cc.
Your combustion chamber size is 58cc.
Add them all together and you have total cylinder volume:

617.78 + 5.5 + 9.68 + 58 = 690.97cc

Now, you divide that number by the total volume above the piston, or

58 + 5.5 + 9.68 = 73.19cc

690.97cc / 73.19cc = 9.4407705:1 Compression Ratio.

Take care,
-Chris

07-17-2002, 05:19 PM	#8
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	4 notches means the same piston can be used in any cylinder. The formula is as follows: Cylinder volume for a 302 is 617.78cc. The space above the top ring, and the space for the 4 notches, is 5.5cc. The average head gasket has a crushed thickness of .047", which equals 9.68cc. Your combustion chamber size is 58cc. Add them all together and you have total cylinder volume: 617.78 + 5.5 + 9.68 + 58 = 690.97cc Now, you divide that number by the total volume above the piston, or 58 + 5.5 + 9.68 = 73.19cc 690.97cc / 73.19cc = 9.4407705:1 Compression Ratio. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!