[Goose]

At our local sprint car tracks, they verify the engine displacement by connecting a clear plastic tube with disc-shaped piston to the spark plug hole in the head. With the rocker arms disconnected from that cylinder, the engine is turned over. The volume of air from the engine cylinder being transferred to the tube and moving the tube's piston. Calculating the volume of air displaced into the tube and multiplying by the number of cylinders results in the cu.in. of the engine.

Without the bore or the stroke measurement, you will not be able to calculate the other.