Figuring displacement?

You are incorrect GOTDART. BJR's formula is right. 6.2832 (8 cyl.) is pie doubled. Half (3.1416 pie) for 4 cyl. and 75% (4.7124) for 6 cyl.
Bore X Bore X Stroke X constant. 6.2832 (8)
4.7124 (6)
3.1416 (4)
Terry.