No, the stock Zetec TB is 55 mm and the V6 is also 55 mm but they are different throttle bodies. The SVT 2.5 V6 and the 3.0 V6 are 60 mm stock.
People measure different parts of the TB when they quote sizes. The correct dimension is to measure the diameter of the bore where the throttle plate is located.
The throttle plate sits at an angle when closed, 7.8 deg for the Zetec, so the plate has an oval shape.
When I machined my 57.6 mm TB I had to make a fixture to hold a brass plate at 7.8 deg inclination while I machined it to 57.60 mm (-0.076 mm clearance) diameter. After removing the part from the fixture it was 57.6 mm across the short axis and 58.13 mm across the long axis.
57.6 mm Zetec throttle body
