Geometry tells us the volume of a cylinder is the circular cross-sectional area of the cylinder (BP certainly knows this because it knows the radius of the pipe is 10.5 inches) multiplied by the ...

A V-6 fires a cylinder every time the crankshaft turns 120 degrees (720/6=120). That would imply a 120-degree angle between the banks, but that configuration is impractical for packaging reasons.