A model T standard piston must show a 0.60 measure?
That would be 600 thousandths. Over 1/2 inch oversize. Are you sure it isn't .060? .060 is 60 thousandths and the cylinder can be bored to fit that size, but 600 thousandths would bore right into the water jacket! The standard piston usually doesn't have any number stamped on it.
Rodrigo......The engine's standard bore is 3 3/4 inches (95.25 mm).......that's the bore, not the piston diameter.
You will read slightly under on the piston.
I just measured a piston and got 3.746" (9.5 cm).