Anyone know what size pistons these are?

[Boner]

Is there any way to tell what size piston you have by the numbers on the top of it? I was told it was 40 over and I'm needing new pistons and want to make sure I order the right ones. After I got the carbon cleaned off the tops the numbers read 50-520-07p and 1.00 below them. The only other markings I could find was on the inside on the skirt which read WSM. Any help in figureing out what size and make they are would be greatly app. Thanks.

[98_shee]

65mm.

[baker]

ya he's correct its 65mm and that is 40 over .040