1965-1970 Ford Mustand Appraisal


DEAL or NO DEAL …..Verify a 1965 – 1966 Mustang Factory GT

Is it a real or fake Mustang GT ?


GT package includes:

-Front fog Lights

-‘A’ or ‘K’ code engine

-Tight ratio steering box on cars with manual steering.

-Front non-power disc brakes, rear drums

-Dual exhaust pipes run through rear valance ends in trumpet tips

-GT badges and stripe / bright rocker molding and quarter panel trim deleted

-Special handling package with large diameter sway bar; heavy duty front coil and rear leaf springs

-Five-dial instrument cluster instead of rectangular Falcon style on the 1965 cars

Exterior & Interior Obvious


Let’s start with the easy stuff.  A quick walk around of this black car shows GT badge’s and stripes.  On GT’s

(and all Fastback cars, both GT and non GT) the bright trim on the rear quarter panel is deleted.


 On an impostor GT there might be evidence of the removed Pony emblem, script, quarter trim and rocker 
panel molding as found on this regular production car. Look for holes that have been filled in for the mounting 
pins. It’s hard to tell unless we remove the front fender and look at the unpainted backside.  Reproduction fenders 
(that have been put on fake GT cars) won’t have the holes so unless we know the car has an original fender it’s not 
a definitive check. 





Here is a close up of the Pony emblem and Mustang script found on non GT cars, like the green one directly above. The lettering is attached at the bottom, making the script one contiguous piece.










Here we have the GT badge and stripe.  Each individual letter
 of the Mustang logo was on a separate pin. It would be nice if we
 could pull the fender to see if the holes for the logo were factory
 punched … I don’t think the owner would be too happy with us! 

The rear of the car shows the dual ‘Trumpet’ exhaust coming out the rear valance panel and the GT

emblem on the gas cap. You could order all the other options described in this article separately,

 but not the exhaust through the valance. It was an exclusively part of the GT package.





Look at the rear valance and frame rails to see if there is any evidence that the car used to have the vertical bumperettes bolted onto the car.


 Assuming the car has the original valance If so, that should set off some alarms.  They can’t be installed with the exhaust pipes properly routed through the valance, and were not offered on the GT cars.








The front was distinguished by fog lights. These could be installed on any car as a dealer option.

We will talk more about the fog light switch and wiring later.


The last interior items to check are the disc brake pedal and the fog light switch. The pedal will have bright trim and say “Disc   Brake” on it ... .These pads are available aftermarket and could be added along with a front disk brake kit. The fog light switch is located on the lower dash on the far left side.  Reach behind and unscrew the keeper that holds the switch to the dash. Many factory GT fog light switch's had a D-shaped hole punched at the factory. Some have a 3/4 inch round hole for the switch. If it has the D shaped hole it is a good sign, but a round hole does not mean it not a factory GT.


Copy of Rose Lane GT_44      fog switch


Data Plate& VIN


Let’s open the door and examine the data plate.  It is a stamped metal tag located on the on the inside of

the driver’s door, near the latch mechanism. 

White-Steves 012

Here we have a 1965 plate. There are many references that will help you decode the numbers and letters, including http://www.mustangdecoder.com/decoder.html  This is an original Prairie Bronze color car with the ‘A’ code engine.  Look at the “28E” build date of the car. The planned build date for the car was April 28, 1965. The GT package became available in mid April of 65, so this falls within the realm of possibility of being a factory GT.


The VIN (warranty) number should match the one stamped under the hood, and be substantiated by DMV records.   The VIN by itself and corresponding DMV records will not designate the color or any other info, and will not document the car as a GT. The VIN will tell us which of Ford’s three factories (San Jose, Metuchen or Dearborn) made the car, and what engine was installed  There are companies that will stamp and sell you a reproduction plate complete with correct four slit ‘star’ pattern rivets.  Therefore we have to rely on the under hood fender apron stamp (substantiated by DMV historical data) to make sure a subject car was made with an ‘A’ or ‘K’ code engine. These were the only engines available with the GT package.



This data plate looks to be in suspiciously good shape. It is a reproduction. The font at all three assembly plants for the 1965 model year was larger as shown in the previous door data plate. The fonts for other years varied.  Another way to tell if a tag is original is to look at the axle and trans codes. The two numbers are right were one would assume that they should be. Ford, however, did not do it like that. On the first (burgundy) tag and on the (blue) one below, you’ll notice that the two numbers are shoved together underneath trans, almost like a two digit code for trans, leaving axle blank. That’s how most original tags are. You can pay a little extra and get a reproduction tag made that way. If the codes are like the one on this D code convertible, it is most likely a reproduction. .


66 data plate_1

The layout of the 1966 plates changed. The warranty (VIN) number was moved to the top. 

It has the same information as the earlier plate.


There are no Ford VIN number records or additional information for 1965 1966 cars. We are left on our own to decide if the dataplate is original and authentic, and to make an educated guess as to whether a car is a factory made GT.  For 1967 and later cars there are records. Kevin Marti has a long standing relationship with Ford Motor Company.  He has acquired and organized all the 1967 and later production data, and is licensed by Ford to provide the information to owners.  If you have what you believe to be the authentic VIN number of a car you can contact him via http://www.martiauto.com and get the ‘Marti Report’ for your car.  Kevin has personally spoken to a computer programmer at Ford who said, "I'm the guy who pushed the button that erased all the '66 data." No one has records for the 1965 and 1966 cars.


Now let’s open the hood…..…..




mustang VIN number

On the driver’s side fender apron you will find a notch with a stamped eleven digit VIN number.  The fifth digit should be an ‘A’ code for the 289 V8 engine with 4 barrel carb, or a ‘K’ for the high performance version.  The star symbols before and after the VIN made it harder to alter the numbers.





This stamp is the legal record of the VIN on the car.  In most states it is illegal to alter, change, remove or restamp it without DMV or Police oversight.  There are stamps hidden in two other locations. One is on the passenger fender apron, under the fender lip. The third is near the hood hinge on the driver’s side, again under the fender lip. The front fenders must be unbolted to see these other VIN number stamps.


Since VIN numbers are corroborated by DMV records, one would have to have a junk car with records to provide paperwork for an altered car. In a cars 40 year history it is possible that the VIN numbers on a car have been forged. There are reports of scam artists taking the ‘identity’ of a rare hi-performance K code car (from a rust bucket or a car that was in a horrible crash) and transferring it to a less valuable, altered car.


Sway bar



 Refer back to the previous picture, find the sway bar. This car does not have the power steering unit blocking

access so it is easy to reach down to it. Take a micrometer or calipers and measure the diameter. If you don’t have a micrometer, see if a 3/4” open end wrench will fit over it.  The GT cars (and all ‘K’ code cars, GT or not) had the ‘handling package’ with heavy duty suspension, and larger diameter sway bar.   The regular sway bar measures  5/8 “, the heavy duty version is a tad fatter, over 13/16” . If you place the wrench square over the fatter bar, it will not fit.



     Steering box, Brakes & Master Cylinder


brake master

Take a look at the single pot master brake cylinder; the GT and all front disc brake cars used an oversize cylinder with a clip on cap; drum brake cars had a screw on cap. You can purchase a new (aftermarket or rebuilt) master cylinder, so it alone does not prove or disprove an original disk brake car. Also, many original disc brake cars have been modified and fitted with a later, safer two pot, two brake circuit system.



Note the old proportioning valve that distributes brake fluid in the correct volume and pressure to the front and rear brakes.  Below is a picture of the valve removed from the car.


proportioning valve



You will have to get underneath the car to

check if it has factory disc brakes.



Gt stering box_resize

The 1965-1966 cars cars be ordered with manual or power
steering. A disportionate percentage of the GT's had the manual
steering, which makes sence for a tight, sporty responce vs.
creature comforts.

For manual steering cars: find the tag on the steering box. Manual steering cars will have the letters HCC AX (tight ratio 16:1 ) or HCC AT (regular ratio 19:1). Most of the GT cars came with the tight ratio box.  The box takes some work to change; the tag does not.  A brand new tag can be purchased and then ‘aged’. One sure way to tell if a car has the tight ratio box is to jack the front up and count the number of steering wheel turns it takes to go from stop to stop.... 3 3/4 turns from lock to lock with the tight ratio and about 41/2 turns with regular.

All power steering cars came with a HCC AW (16:1) box so the ratio does not tell us anything. Below are some more examples of steering box tags that have been removed form the box.




Fog Lights



There has been a lot of talk about the proper size and shape holes in the radiator supports that routed the fog light wires from the grill towards the wiring harness and the dash. The consensus is that there were two 11/16” two holes made at the factory for the wiring. Note: On early cars there is sometimes only one hole on the passenger side, & the driver side wire is routed through the inner fender apron.


If the car has the original factory wiring harness, when the foglight switch is turned on the rear lights should also light up. The foglights had a circuit breaker was mounted to the brake pedal support or the wiper motor mounting on a factory GT.




Fog-light-holes-detail_1 GT-project 021_exposure

Here are the details of the fog light holes on both the drivers and passenger’s side.





Take a careful look at the back side of the holes. This one has a slight bevel around the edge. The hole has most likely been punched at the factory, as opposed to drilled in someone’s garage. I have seen the holes punched and drilled on factory GT’s….so it is not 100% proof of a factory fog light car. If you come across one that does have the bevel it is a really good indicator, though.


Bezels & Dash


The gauge and glove box bezels are particular to the GT (and Pony Interior) cars. ’65 non-GT cars had a rectangular speedometer face, see below. The ’65 and ’66 GT cars both had round dial speedos. The black border stops halfway down the face.  The Pony Interior cars have fake wood grain decals. Instrument bezels and glove boxes are easily changed; this indicator by itself does not verify a true GT.


UPDATE: Look at the 1966 GT instrument bezel and glove box pictures below. I have reports that some 1966 (non-pony interior) GT cars have original bezels with black border going all around the face; same as the non-GT cars (which means 1966 GT non-Pony Interior might have the bezels shown in # 3 and # 6 below).





On a 1965 model car with the GT package or Pony Interior, there will be a round cut in the dash along the bottom to accommodate the round speedo. A car that came with the rectangular Falcon-style instrument cluster will be straight across the bottom.


All the 1966 cars had the round cut (both GT and non-GT cars had the round speedo).




The ammeter gauge in a 65 GT or pony interior car is different from a 66 model car. The ammeter gauge does not have the two posts sticking out of the back of it, like a 66. It has a metal  loop sticking out of the back, and the main power feed wire ( black with a yellow stripe) passes through that loop and the gauge sense the direction of current flow. So, a 65 GT car, if you pull the instrument cluster out a little bit, should show the dip in the dash and an ammeter gauge that has no wires plugged directly into it. (NEED PICTURE)



Dual Exhaust Hangers 


  The next item is going to involve a little work.

back seat back seat reinforce

Sit in the rear of the car & face the back seat.  Push the seat bottom in and tilt it up. Look under the seat back for the small metal backings for the dual exhaust hangers. The floor pan sheet metal is reinforced in this entire area.



GT-project 016

Here is a better picture with the entire seat back unbolted and removed. You can see

The double reinforced sheet metal that encompasses the exhaust hangers & seat belt anchors


There is another check for factory dual exhaust. From under the car look at the rear frame rails, where the rear exhaust hanger attaches, just ahead of the shackle. There should be a metal bracket towards the rear, between the inside rails where the hanger bolts go through the frame. The bracket was welded during production of the car so that the exhaust hanger bolt wound not crush or deform the rail. You can feel the bracket by inserting your pinky finger into the hole and feeling towards the rear of the car.







You can also check for the bracket by opening the trunk and sticking your finger through the hole on the top of the rail. There is a tubular bar down inside the hole. If you stick your finger under and a little to the other side, you will hit a solid plate . On a single exhaust car your finger will keep going forward.











Here is a close up view of the hole in the trunk where you will check for the plate  it will be under the tubular bar.















Conclusion & References


Unless you have an original "buck tag", build sheet or dealer invoice there is no way to verify with 100% certainty if a car is a factory GT. All we can do is check details on the car and make an educated guess. If one of the GT components integral to the body (i.e. reinforced sheet metal for dual exhaust) is missing, the car is probably not a GT. Checking add on components such as Fog Lights etc. helps a little, i.e. if a car has 1960's original FoMoCo fog lights it is a good sign. Even so these parts can be purchased as swap meets, from private parties etc. so they are not definitive signs.



Some non-GT cars had many of the GT options, and were completed at the dealership as GT ‘s with 1960’s vintage factory made parts. For the purist, these are not ‘factory’ GT cars. These are the ways to determine with that a car is not a factory GT:


1) If the car is an early 1964 1/2 model it is not factory GT.


2) If the car is not a K code or an A code, it is not a factory GT.


3) If a 1965 model car does not have a clean, factory cut in the dash bottom for the speedo, it is not a factory GT. Having the dip does not mean that it definitely is a GT…the dip is also found on 1965 Pony Interior cars.


4) If the car does not have the reinforcement inside the rear frame rail for the exhaust hanger and behind the rear seats, the car is not a factory GT (unless the unibody has been altered).


5) Early cars: If the car does not have at least one cutout in the passenger radiator support for the fog lights, it is not a probably not factory GT. The later cars will have two cutouts.

As for the bolt on features (steering box, foglights, suspension components), the presence or absence of these does not prove or disprove a GT. A non-GT car might have been ordered and factory built with some of GT options. The 1965 Pony Interior cars came from the factory with the bezel dip. Other cars had options added at the dealership or after the car was sold. The bottom line is this:  For the 1965 and 1966 cars there are no Ford Motor Company records matching VIN numbers with original build information.  Unless there is original 1960’s documentation, like a Buck Tag ( can be ordered as stamped reproductions) or Build Sheet proving that a car is a factory GT, all we can do is make an informed, educated guess.


Thanks to Veronica Sczbecki for contributing to this article. She has lots of excellent, practical early  Mustang info on her blog http://thecareandfeedingofponies.blogspot.com


Thanks to Kevin Marti for reviewing this article, and for his comments.  For more detail about how to spot a fake data plate tag, and information on decoding the engine, transmission, buck, VIN, and all other tags on your car see his

Mustang and Cougar Tagbook http://www.martiauto.com/itemselection.cfm?id=1964


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