http://www.edelbrock.com/automotive/math.html
Formula for CID (cubic inch displacement)
CID = NUMBER OF CYLINDERS x SWEPT VOLUME
Note: CID = N x 0.7854 x bore x bore x stroke (all in inches)
Example: What is CID of a V8 with a “30 over”, 4 inch bore and 3.48 inch stroke?
CID = 8 x 0.7854 x 4.030 x 4.030 x 3.48 = 355 cu. inches
or you could use Volume = Pi X r(squared) X H
About Compression Ratio
Formula for CR
CR = COMPRESSION RATIO = CYL. VOLUME @ BDC ÷ CYLINDER VOLUME @ TDC
= 1 + (SWEPT VOLUME ÷ VOL @ TDC)
= 1+ (0.7854 x BORE x BORE x STROKE) ÷ (CCV + HGV + PDV)
CCV = Combustion Chamber Volume, in cubic inches
Note: if volume is given in cc’s then ÷ 16.4 to get cubic inches.
HGV = Head Gasket Volume, in cubic inches,
= Head gasket compressed thickness x 0.7854 x bore x bore
PDV = (Piston Deck Volume) + (Piston Dome Effective Volume)
= (0.7854 x bore x bore x deck to piston distance) + (volume of piston depressions - volume of piston bumps)
Example: What is CR of the engine in #9 if heads have 72 cc chamber, head gasket is compressed to 0.040 inch and flat top pistons give 0.025 deck clearance at TDC?
CCV = 72 ÷ 16.4 = 4.39 cubic inches
HGV = 0.040 x 0.7854 x 4.030 x 4.030 = 0.51 c.i.
PDV = 0.025 x 0.7854 x 4.030 x 4.030+ 0- 0 = 0.32 c.i.
CR = 1+ (0.7854 x 4.030 x 4.030 x 3.48 ÷ (4.39 + 0.51+ 0.32))
= 1+ (44.39 ÷ 5.22) = 9.5 CR
http://www.edelbrock.com/automotive/math.html