Group 3 Pantera
While a Group 4 Pantera is a dedicated, purpose-built race car that used Pantera architecture but a unique chassis and suspension, the FIA Group 3 rules were far more restrictive, as the FIA intended for this class to consist solely of essentially stock, unmodified production sports cars. Initially, modifications from standard, production-car specification were few, mostly relating to pure safety issues, but after a few years, as the series evolved, the list of allowable modifications grew for all cars competing in Group 3.
Unlike the Group 4 Panteras which were built utilizing special components, all Group 3 Panteras were constructed from ordinary, production-line European Panteras. As they were all built to individual customer order, it’s difficult to generalize about them. Furthermore, the nature of bespoke De Tomaso automobiles makes it even more difficult to differentiate between different models, since it was possible for any European customer to order each of the components used to create a Gr3 Pantera directly from the factory, and modify a standard car to that specification after the fact and then race it.
It was also possible to order a Euro GTS and then have it built with all the Gr3 components at the factory. So there is a very fine line between a factory-built Gr3 race car, a Euro GTS fitted with Gr3 components, and a race car converted to Gr3 specs by a private party. While the De Tomaso factory public relations personnel are extremely helpful, and are capable of answering a query to determine if a specific car was constructed as a Gr3, at this time they don’t have a complete list of all Gr3 cars made, but they have committed to researching the information for the next edition of the De Tomaso registry.
The process of building a Gr3 Pantera started in the engine room. De Tomaso certified the Gr3 Pantera with either a standard cast-iron intake manifold and Motorcraft carburetor, or an optional aluminum Ford manifold with a Holley R-4777 650 cfm manual-secondary carburetor. The stock oil pan was replaced with a large (8 liter on early cars, 10 liter on later cars) pan with an integral windage tray and an optional removable chassis crossmember.
Standard exhaust manifolds, and later European GTS exhaust headers were fitted (consisting of 4-into-2-into-1 headers with a 2 1/2 inch collector), and the 2 1/2 inch tailpipes fed into either low-restriction ANSA GTS mufflers, or the so-called Gr3 mufflers (GTS-style muffler cans with no internals, and hence no sound-reduction capabilities.) Finally, the entire muffler assemblies could be deleted and replaced by simple straight exhaust pipes. One would hope the engines were thoroughly checked over and received careful blueprinting and hand-assembly at the factory, but there is no evidence the De Tomaso engine-builders weren’t simply affixing these bolt-on parts to otherwise-standard engines.
The radiator was unmodified, although optional 8-bladed fans replaced the standard units. The chassis received only subtle tweaks initially. The same Ariston adjustable shocks fitted to conventional Panteras were standard on the Gr3 version, but there were two levels of Koni shock upgrades available. The first featured internal rebound adjustment only, while the top-of-the-line shocks had a threaded aluminum body with ride-height adjustment, and external controls for compression and rebound adjustment, with over 100 different combinations available. The top-of-the-line shock package cost an additional $1,000 back in 1973, quite a serious investment when you consider you could buy an entire street Pantera for under $10,000!
The Gr3 Panteras were equipped with the same springs as the European GTS, with only one optional spacer listed (presumably for rally cars.) The steering rack was repositioned using spacers to alleviate bump-steer concerns, but the control arms and sway bars were the same as those fitted on production Panteras.
The brakes consisted of standard Pantera calipers squeezing ventilated discs measuring 282mm in diameter and 20mm thick, and actuated by a standard master cylinder; this was a common option for Euro GTS Panteras as well. Standard 7- and 8-inch Campagnolo wheels and Michelin radial XWX 185/70 and 215/70 tires were fitted.
In 1974, the FIA approved further modifications to the suspension. The rear hub carriers and front spindles were replaced by heavier Group 4 units, and the brakes were changed by using a larger master cylinder, larger cast-iron three-piston front calipers with 288mm x 31.75mm front rotors, and larger cast-iron three-piston rear calipers with standard GTS vented rotors and stronger axles with heavy-duty wheel studs.
Although similar in appearance, these were not the same brakes as used on the Group 4 Panteras, but this system later became standard issue on the GT5 and GT5-S. Small auxiliary rear calipers with their own small pads were used for the parking brake.
The stock sway bars were replaced with an adjustable system, philosophically similar to, but mechanically different from, the adjustable bars featured on the Group 4 Panteras. The then-common 10-inch Campagnolo Euro GTS wheel was allowed for fitment in the rear, and 8-inch wheels were issued for the front.
The interior of the Gr3 Pantera was surprisingly mundane. Earlier cars had the two-pod dashboard, while later cars received either the one-piece molded USA L-model dashboard, or the similar-appearing two-piece upholstered Euro GTS dashboard; all were fitted with metric gauges and European switchgear. The stock seat belts were retained with a race harness installed for the driver only, and the standard Pantera seats were supplanted by one-piece racing bucket seats, the same as those in the Group 4 Panteras.
(Interestingly enough, these one-piece racing seats were actually constructed from the remains of the prototype Pantera’s radical “picket fence” seats. Those seats consisted of a sheetmetal frame, fitted with yellow foam blocks. Visually striking, but judged by Ford as being too weird for the marketplace, they never went into production. As De Tomaso had already produced many of these frames, they simply upholstered them with light padding and turned them into race car seats.)
Heavily padded bolsters, as used in the Group 4 cars, were sometimes fitted to the door panels on one or both sides.
On some cars, the ignition switch was later relocated from under the dashboard to the middle of the center console, behind the ashtray, and within easy reach of the driver while he was belted in. A fire extinguisher was bolted to the floor in front of the passenger seat.
The USA-model steering wheel was standard equipment, but buyers had the option of fitting the three-spoke Euro GTS Momo Prototipo wheel or the smaller Group 4 Momo Prototipo wheel instead. Interestingly, the Gr3 Panteras were sold with full heating and air conditioning, electric windows, a radio aerial bolted to the roof, and a pair of speakers installed in the center kick panels (one in front of the gas pedal, and the other pointing into the passenger footwell), but no radio was included. Air horns were also optional.
The plexiglass rear window and six-point roll cage of the Group 4 Pantera were standard issue in the Gr3 cars as well. Furthermore, the front engine cover was modified to allow easy access to the front of the engine without requiring the removal of the entire back panel (which would have required removal of the roll cage!)
Cosmetically, the Gr3 Panteras slowly changed as the production Panteras changed. Early Gr3 cars carried standard two-piece front and rear bumperettes. After the introduction of the L-model Pantera, some Gr3 cars were equipped with early-style front bumperettes incorporating the front turn signals, while others had European L-model bumperettes with the turn signals residing in the standard L-model pods on the underside of the front fenders. Turn signal lenses were either clear with a colored bulb, or bi-color with an amber and a clear section.
Some cars retained two-piece rear bumperettes while others received the European L-model one-piece rear bumper (which was the same as the USA L-model bumper, except that instead of being mounted on hydraulic rams, it was mounted on solid brackets, considerably closer to the car’s body.) Both front and rear bumpers on Gr3 cars were normally chrome.
There were various driving and fog light packages issued; some cars received Carello fog lights, while others received massive lighting arrays for nighttime rally racing. For the first few years, a simple flat blade front spoiler with cooling ducts for the front brakes was installed while later cars got a miniature air dam (also a common option on the post-1976 European GTS) and small, riveted-on GTS flares.
Apparently few of the Gr3 cars received the Euro GTS paint scheme, with a blacked-out front hood and rear decklid and blacked-out rocker panels. The Gr3 Pantera shown in the factory brochure and postcards is solid yellow. In most cases, the European GTS rocker panel decal (which said “De Tomaso” in large letters, then had the words “Pantera” in smaller script, above the word “GTS”) was used, but modified to delete the mention of “GTS.”
As with the Group 4 cars, rubber tie-downs were used to secure the front hood and rear decklid, although unlike the Group 4, the sheetmetal was standard steel instead of aluminum. An external battery cut-off switch without a removable key was fitted to the right front fender; the same switch was mounted on the the Group 4 cars.
The documentation on racing Panteras is sketchy at best; it’s difficult to say exactly how many were built. At least one owner claims that his Gr3 is one of only 10 cars produced by the factory, but the De Tomaso Registrary now lists at least 13 claimed Gr3 cars (although it’s possible that some of those were converted from regular production Panteras.)
This description of the Pantera Gr 3 came from a from the "De Tomaso of the Quarter - Dale Eriksen’s 1973 Pantera Gr3" article written by Mike Drew and publsihed in POCA Profiles 2000 No. 3. Here is the original article with pictures in PDF format [405 KB].