On a 1960 Ford F-100, the Vehicle Identification Number (VIN) is stamped on the
dash panel, usually on the
driver's side, visible through the windshield. It's often located near the area where the dashboard meets the cowl.
However, 60 years of age and potential previous repairs mean it might be difficult to read or even partially obscured. You may need a flashlight and possibly a mirror to get a good look.