Compression Calculator

Simply fill in the form below to calculate your compression ratio

Bore: (diameter)
Stroke:
Cylinder Head Volume:
Effective Dome Volume: ^{Use (-) for Dome and (+) for Dish.}
Deck Clearance:
Compressed Gasket Thickness:
Number of Cylinders:
Compression Ratio :
Total Displacement (in.³) :
Total Displacement cc's :

The cc for the piston is entered as a positive number on a -cc Dish or Flat top piston and a negative number on a dome piston. This seems very confusing but it is because even though it is a -cc on the piston, those same cc's are gained in cylinder volume. Hence the positive number in the calculator. Same goes for a dome where it is positive cc's on the piston but a reduction in cylinder volume. Hence the - (negative) number in the calculator.

Popular Block and Bore Sizes Compression Chart

400 Block		Head cc w/-8cc Flat top
Stroke	Bore	72cc	87cc	96cc
3.750"	4.155"	10.38	9.02	8.38
	4.181"	10.48	9.11	8.46
4.000"	4.155"	11	9.55	8.87
	4.181"	11.12	9.65	8.96
4.210"	4.155"	11.53	10	9.28
	4.181"	11.65	10.1	9.38
4.250"	4.155"	11.63	10.09	9.36
	4.181"	11.75	10.19	9.46
4.500"	4.155"	12.25	10.62	9.85
	4.181"	12.38	10.73	9.96

428 Block		Head cc w/-8cc Flat top
Stroke	Bore	72cc	87cc	96cc
4.000"	4.155"	11	9.55	8.87
	4.181"	11.12	9.65	8.96
4.210"	4.155"	11.53	10	9.28
	4.181"	11.65	10.1	9.38
4.250"	4.155"	11.63	10.09	9.36
	4.181"	11.75	10.19	9.46
4.500"	4.155"	12.25	10.62	9.85
	4.181"	12.38	10.73	9.96

455 Block		Head cc w/-8cc Flat top
Stroke	Bore	72cc	87cc	96cc
4.000"	4.181"	11.12	9.65	8.96
	4.211"	11.25	9.76	9.07
4.210"	4.181"	11.65	10.1	9.38
	4.211"	11.78	10.22	9.49
4.250"	4.181"	11.75	10.19	9.46
	4.211"	11.89	10.31	9.57
4.500"	4.181"	12.38	10.73	9.96
	4.211"	12.53	10.86	10.07