piston88Instructions: Enter a value in the un-shaded boxes below as they pertain to your engine. Note: For pistons BELOW the block @ TDC – value in box must be a POSITIVE number (.000) Note:Instructions: Enter a value in the un-shaded boxes below as they pertain to your engine. Note: For pistons BELOW the block @ TDC – value in box must be a POSITIVE number (.000) Note: