Piston - Selection

NOTE: The cylinder bore must be within the specifications for taper and out-of-round before fitting a piston.

Select a piston size based on the cylinder bore.

Fig 1: Identifying Cylinder Bore
Courtesy of FORD MOTOR CO.

NOTE: For precision fit, new pistons are divided into three categories within each size range based on their relative position within the range. A paint spot on the new pistons indicates the position within the size range.

Fig 2: Identifying Piston Paint Color Spot

Courtesy of FORD MOTOR CO.

Choose the piston with the correct paint color.
- For additional information, refer to the appropriate ENGINE article for piston grading.