VECI Label under hood above master cylinder
For the label specific to YOUR vehicle, click
this link, then click "Quick Guides" in the sidebar, then click "VECI Labels" and find the calibration code on the sticker on your EEC. On '87-91 F-series & Broncos, it's in the driver's kick panel. '92-96 is in the same place, but it's not visible without removing the EEC into the engine compartment. Some '92-96 trucks also have the calibration code on a sticker in the door jamb, but it's hit-or-miss; I haven't found any pattern.
For carburetors, try this:
http://www1.autozone.com/servlet/UiBroker?ForwardPage=az/cds/en_us/0900823d/80/0c/e6/05/0900823d800ce605.jsp 
