Automotive trades: Total piston displacement is given by the following formula: P.D. = piD^2LN (pi is over 4)
P.D. = piston displacement in cubic in.
D = diameter of bore of cylinder
L= length of stroke, in inches
N = Number of cylinders
A. P.D. = 400 cu in. L = 4.5 in. N = 8
B. P.D. = 392.7 cu. in. L = 4 in. N = 6