389 Compression Calculator

Simply fill in the form below to calculate your compression ratio.

Bore (diameter)

Stroke

Cylinder Head Volume

Effective Dome Volume(-) dome, (+) dish

Deck Clearance

Compressed Gasket Thickness.040 is standard thickness

Number of Cylinders

389 Block — Displacement Reference

Over	Bore	3.75" stroke	4.00" stroke	4.25" stroke	4.50" stroke
Stock	4.062	389	415	441	467
+.030	4.092	395	421	447	473
+.040	4.102	396	423	449	476
+.060	4.122	400	427	454	480