Your Chevy 350's bore is an important measurement for its power, torque and general performance. The bore is the diameter of the cylinders, and the wider the bore the more effective the 350's compression. As time goes by, a cylinder can become warped, making the bore either too large or too small at various points within. This makes the engine less effective, as the pistons either cannot move as fast or as hard or, if the bore is too big, cannot compress as effectively. To measure your bore, you need to use a bore gauge.
Calibrate the gauge by setting its teeth to the bore size you need, then turning the dial on top until it is at zero.
Place the teeth inside the cylinder and turn the dial that spreads them apart.
Check the reading. If it is above zero, then the bore is too large; if it is below zero, then it is too small.
Repeat this process through several points in the cylinder, as expansion and compression are not uniform processes.
