So I'm in the market for under-drive pulleys, but I want to make sure there isn't a set already on there. Can anybody give me the diameter of the stock pulleys? Or, if there's another way to tell whether or not I have stock pulleys. Do all of the stock pulleys say ford, or just some of them?
The first way to tell is to see if the crank pulley has been changed. Stock is aboput 6 -7/8" lip to lip. An underdrive will be about 5" lip to lip. Having gone the route with underdrive pulleys I wouldn't recommend them.
They are usually a different color than the black steel stamped OEM units. Some do them in blue, grey, polished, etc. Haven't seen them in OEM black unless someone paints them that color. All my pulley's were polished.