1968 Mustang / Shelby

Production Variations

Understanding the production cycle is the key to understanding production changes and how they relate to your car. 1968 Mustang production began in very late August 1967. This was so the new cars would be available in dealer showrooms by October. Mustang production was interrupted from September 7, 1967 through November 11, 1967 during the United Auto Workers strike. Unfinished cars sat idle in the plant for nearly eight weeks. The strike did not greatly effect 1968 Shelby production. 1968 Shelby production lasted only nine months from November of 1967 until the end of the model year in July of 1968. Although some cars were sent to AO Smith for conversion before the UAW strike, this number was likely less than six. GT500 KR production started at the end of April 1968, but was mainly during the last three months of production.

It is true all 1968 Shelbys share a very small set of options and most options were "mandatory". There were several running production changes during the production cycle. I will list some of them here and briefly discuss the variations. Several of these variations can be directly traced back to production changes at Ford's Metuchen, New Jersey assembly plant. While other changes were made at AO Smith. A 1968 Shelby will actually have two important production dates. The first is when it was assembled by FORD in New Jersey. The second is when it was completed by AO Smith as a Shelby.

Production changes at Ford

GT500 Engine Coding All GT500s were originally equipped with FORD's 428 Police Interceptor engine. The engine was designated by an "S" engine code. This code was also used on the FORD's 390 engine. Ford sent out a special letter to explain this oddity.

Rear Axle Coding Coding All Shelby models had a specific rear axle that was matched to their drivetrains. Axles could not be special ordered by customers. The axle codes used by FORD for 1968 Shelbys are not the same as the codes used on standard Mustangs.

Build Tag Coding The actual codes found on the build tag change during the model year. This is why these codes mystery for almost 40 years. With the help of Ford records all codes have been decifered.

Exterior Sheet Metal One of the most prominent changes is to the exterior sheet metal of the 1968 Mustang/Shelby. The rear quarter panels change halfway through the Mustang production cycle in mid- Febrauary 1968. Early cars have a recessed quarter panel with a special chrome trimmed reflector. Later cars have an oval reflector that is flush mounted. All GT500 KRs were built after the change over and should have the later style reflectors. This is an easy way to establish if a body was built "early" or "late" in the production sequence.

Convertible Seat belts The mounting locating for the convertible, rear seat belts change during the 1968 production year. Later cars have the seat belts have the belts mounted to the floor, earlier cars do not.

Production Hardware Throughout the model year the hardware used to build Mustangs has subtle changes. Changes in hardware head designs (vendors) are common.

Warranty Plates During the production model year there were at least four variations of the warranty door tag. These tags change throughout the year and not all tags say "special performance vehicle" on them.

Hood Seal The forward radiator/hood seal maybe either stapled or screwed in place. It appears both methods were used throughout production.

Interior Pillar Pads Pillar pads are pads located on either side of the windshield ("A" pillar). They are common to cars built early in the production cycle. Later cars do not have the pillar pads. The change over was around the same time as the changes to the rear quarter panels.

Interior Dashboard Padding The same is true of the "knee" pad above the glovebox. The change over date is not the same. So, it may be possible for some cars to have one, but not the other. Knee pads go through the end of 1967. GT500 KRs should not have pillar pads or knee pads.

Tilt Columns The tilt steering wheel is not present during the first few weeks of 1968 Shelby production. It later becomes a mandatory Shelby option. In fact, most tilt wheels were installed in Shelbys.

Steering Wheels Most cars have the deluxe, woodgrain steering wheel. Some cars were produced with a standard black or saddle steering wheel (no woodgrain). These cars all appear to be built in mid-March.

Interior Chrome on Fold Down Seats Most cars do have the chrome strip on the rear interior, fold down seat floor. Some early cars may have came through with the chrome trim attached.

Fuel Line Clamps In the beginning, the fuel line clamps under the body of the car are usually a small whittek style clamp. This later changes to a pinch type or spring type clamp later in production.

Heater Hoses Engine heater hoses start the production year with a white stripe and later change to the more predominant red striped hose.

Dash Gauges Early built cars may have a tachometer without a specified redline. Most cars have a redline on the tachometer.

Tires At least three different tires were used during 1968 Shelby production. They are the raised white, small letter Goodyear Speedway, the raised white, large letter Goodyear Speedway and the Goodyear Polyglas GT - Black side wall. The later was used predominantly on the GT500 KRs.

Distributors Late in the production year the GT500 KR distributors change from the more common C80F-12127-D to a newer style distributor with another part number.

Starter Motors The starter motors were changed after it was found the incorrect versions were being installed on some GT350s.

Air Cleaners Two different engine air cleaners were installed on GT500 KRs by FORD. GT350s and GT500s recieved oval "COBRA" air cleaners at AO Smith.

Engine Vacuum Hoses Most 1968 engine vacuum hoses are a solid colored stripe. Later vacuum hoses use a colored stripe with an "MX" marking.

Speedometer Gears The wrong speedometer gears were installed on some vehicles. These gears were later replaced by dealers in most cases.

Exterior Paint The color Sunlit Gold was discontinued as a Shelby color after numerous color matching problems with AO Smith.

Production changes at AO Smith production.

1968 was the only year three distict models were built. They were the GT350, the GT500 and the GT500 KR. Each car has it's own unique parts. GT500 KRs were built starting at the end of April of 1968. Most of these cars were built during the last three months of Shelby production.

Serialization One of the first changes made at AO Smith was the sequential numbering system. Some early cars actually have a dual serial number. The first number is similar to the standard 1968 serial number. The second number is like the 1967 Shelby serial numbers. Both numbers can be found on the under hood Shelby VIN plate. Early cars use a "Shelby American" plate, while later cars, including all GT500 KRs use a "Shelby Automotive" plate. This change also was made to the door sill plates when the company formally changed its name.

Fiberglass The fiberglass used during 1968 production is one of the most noticeable changes. In the beginning some hand layed fiberglass was actually used. This is very rare. The lower front valence was one the piece that was used in regular repoduction. Changes in scoops and quarter panel end caps are most likely due to differences in the molds. I have seen at least four variations of the production hood, but the differences are minor. Most fiberglass used on 1968 Shelbys is actually a product called Fiberglass Reinforced Plastic (FRP).

Tail light Installation The manner in which 1965 Thunderbird tail lights are mounted also changes during the production cycle. At least three versions of tail light mounting were used during production.

Roll Bar Gaskets At the start of production convertible roll bar gaskets were hand made, later changing to a plastic part.

Fog Light Wiring Fog Light wiring and fog lights change during production. The original Marchal lamps were recalled in favor of the Lucas Square 8 lights. Although not all cars were returned for the recall. Cars built later in the year all have the Lucas lamps.

Production Hardware Throughout the model year the hardware used to build Mustangs has subtle changes. Changes in hardware head designs (vendors) are common.

Intake Manifolds All GT350s were originally built with the cast iron four barrel manifold. The manifold was later recalled. Towards the end of production, the aluminum hi rise intake was used.

Carburetors Carburetors for GT350 and GT500s change throughout the year. The GT350 used both the AUTOLITE and Holley carbs. GT500s used the Holley carbs, with the AUTOLITES appearing for a short run.

Shift Knobs There were several shift knobs used during production. It appears that later 4 speed GT500 KRs were actually supposed to use a wooden Cobra snake knob. The white with blue stripe knob was also used. Automatics usually have the stock shift handle with later cars having the wooden snake t-handle knob.

Door Sill Plates Due to a company name change, door sill plates change from “Shelby American” to “Shelby Automotive”.

Blackout decals The shape of the blackout decals on the back of the hood changes during production.

Exterior Paint All Mustangs were original painted with a single stage acrylic enamel paint by FORD. AO Smith was suppose to use enamel, but sometimes substituted lacquer paint when painting fiberglass panels.