Have you ever stumbled upon a Mustang find with numbers that could not be explained? For example, the warranty plate says 5F07A235545, yet the inner fender stamp says 5F07T235545. What's with the engine code? Do we have a six or do we have a V-8? Obviously, the best answer here is to examine the chassis and engine. If it looks like a V-8, it surely must be a V-8. Where this becomes a problem is with state motor vehicle bureaus. Sometimes titles originate with the VIN gleaned from the warranty plate. Sometimes they originate from the inner fender. Confusion abounds when someone discovers the mix-up.
Mis-stamps weren't all that common, but they did occur. We've found Mustangs with the consecutive unit number on the warranty plate a few digits away from what was stamped into the inner fender. This was an error committed on the final line when one unit received the warranty plate of another. Sometimes the engine code is clearly in error, as we said earlier. Sometimes it's the body serial code. Never have we seen a plant code mis-stamp.
We have seen factory mis-stamps that were caught and corrected. These are mis-stamps where a bunch of X's stamp out the mis-stamp, then the correct VIN (vehicle identification number) was hand-stamped nearby. Sometimes a hand-stamp has happened when an inner fender was replaced by a body shop.
Another area to consider is clip cars and units on which the left-hand door has been replaced. In this case, the VIN on the warranty plate or certification sticker will differ greatly from what's stamped into the inner fender. Clip cars are Mustangs that have suffered a serious frontal or rear-end impact, and had either end completely replaced. These are typically easy to identify. They have a seam where a seam shouldn't be, such as across the floor pan. Most are joined at the sail pillar or in the trunk area. Close internal inspection is vital in this case.
If you have a mis-stamped Mustang, we would like to hear from you with your find. For more information about In Search of Mustangs, write to us at Dept. MM, P.O. Box 883, Annandale, VA 22003, or e-mail us at Jim.Smart@Primedia.com.