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thank you Ron

I ask for 4 reasons

(1) The 15x8 wheels had 19mm off-set, whereas the 15x7 wheels had only 6mm off-set. Installing the 15x8 wheels "as-is" reduced the front track width by 1 inch. To get a car to stick better in corners you normally increase the track width, it doesn't make sense for the factory to reduce it. For instance, the rear 15x10 wheels increase rear track width by a whopping 2 inches.

(2) I've known (and currently know) Pantera owners who have installed 225/50R15 tires on their Panteras, using the 15x7 wheels, without any rubbing issues. Moving the tires inward wasn't necessary due to fitment issues.

(3) I've seen 1970s era pictures of the factory GTS in which the front tires appeared to be moved outwardly further than in other pictures.

(4) Then there's this factory parts diagram which we've all seen a hundred times (below) clearly indicating a spacer for the front. Perhaps the spacer was optional equipment?

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  • gp3_expl_vw
1. My car has 15x8 rims .. I dont see any indication of long studs to accept spacers ... also less factory GTS Flairs ... my car being a later version in 1979 ... they didn't build my car with handling in mind .. it was more cost effective less spacers and flairs.
2. Tire size in the front is 225/50 with no rubbing issues ..even in hard cornering.
3. I think your right and when they moved them outboard that would explain the GTS Flairs.
4. I see the diagram ... i think the tell tail would be longer studs in the front.
5. The rear of my car has 305 /50 which also fit very nice ... i never looked or compared it but at times i thought the car had a wider look at the 1/4 panels

Heres a good picture in a hard corner ...

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  • Rons_GTS_3
Last edited by George P
Very interesting discussion.

I couldn't help but notice that there are components in this illustration that are probably intended for racing, such as the roll cage and the vented rear rotors?

I'd take a guess that the front spacer is probably suggested for competition...of some sort?

I'd also make an educated guess that the spacer there is a 1/2" thick. Looking at my car, I'd expect some kind of interference with that as is (without flares). Probably 1/4" thick would work though?

My thought is that I'm not sure that you need to increase the front track for a handling improvement? Since I don't race and haven't tried every combination, that is just speculation though.

Still a fun thought to consider.

I'm with Ron on the longer studs thought. I would expect those to be shown in the diagram as well as different front calipers to go with the thicker rotors? No calipers shown?

The Gp3 used big ugly non-stock iron Girlings. There are aluminum calipers eventually offered but apparently the aluminum Girling 18-4 and 16-4 units don't appear for the Pantera until sometime AFTER the factory raced the Gp4 cars in 72-73 although they seem to be on everything else but the Pantera?

They are on a couple of the Gp4 cars but might be "aftermarket" additions. That is still unclear at this point.

Example. The GT40 was called the Gulf in the '68 season. It was run with the Aluminum Girlings, and a Boss 302 also. Lola T70 used them. Porsche as well.

Are there more illustrations that go with that one George?
Last edited by panteradoug
George,

It seems to me, the items shown in the diagram are GT3 parts not GTS. The clue is the roll cage. GT3's had wheel spacers on the front, not to increase the track width, so the reinforcing ribs on the inside of the 15x8 Campi wheels would clear the GT3's big brake calipers. Without the spacers, the front wheels won't turn. I know one GT3 owner who found that out the hard way!
quote:

Originally posted by accobra:

Heres a good picture in a hard corner ...



That's some big rubber on the back of your GTS Ron! Smiler I'm amazed it doesn't rub the outer fender. Since the 15x10 wheel has negative 6mm offset, the sidewall of that tire actually extends outward 3mm more than a 335mm tire mounted on a 17x11 Campy clone.

quote:

Originally posted by PanteraDoug:

... My thought though is that I'm not sure that you need to increase the front track ...

... I'm with Ron on the longer studs thought though ...

... Are there more illustrations that go with that one George?



The front track was reduced one whole inch by installation of the 15x8 wheels in the front. I'm curious if De Tomaso compensated for that by adding a spacer. I'm agreed about the need for longer studs. Since 225/50R15 tires can be installed on the 15x7 front wheels without rubbing, I see no reason why that spacer couldn't be 12mm thick because the 15x7 wheels have 12mm less offset than the 15x8 wheels.

That illustration is an incomplete version of an illustration scanned from Jan Norbye's Pantera book. Mr. Norbye's comment below the picture reads "what it takes to make a European spec GTS out of your standard Pantera". I assume the picture is from the "Post Ford" European Pantera parts manual; but that's only an assumption since I don't have a copy of that version of the parts manual.

quote:

Originally posted by David_Nunn:

... It seems to me, the items shown in the diagram are GT3 parts not GTS ...



When the Group 3 Pantera was conceived, it could only be equipped with the same components as the road version save for a few safety items. The standard Pantera was not "race ready" so an improved road going Pantera (the GTS) was a necessity in order to compete in the Group 3 class. The GTS and Group 3 are therefore kissing cousins. The Group 3 was based on the GTS. Or to look at it the other way around, the GTS was created so De Tomaso could go Group 3 racing. After a couple of years the Group 3 rules were relaxed, allowing for a few parts such as brakes to stray from the production items. But ... a customer could have ordered a GTS from the factory at any time, and had it equipped with every part used for the Group 3 as optional items. So ... are we looking at a Group 3 exploded view, a GTS "options" list, or both?

The original wide body road going Pantera, what we call the GT4, was also conceived as a GTS with optional wide wheels/tires and fender flares. It didn't become a model separate from the GTS until 1980, the year the GT5 was introduced. The heavy duty brakes and uprights installed on the GT5 and GT5-S Panteras were sourced from the Group 3 race car.

Anyway, I've digressed. I've never heard of a GTS having a spacer up front. I'm just being thorough, making sure I haven't overlooked anything. Seeking the facts. I'm hoping to be educated. Smiler Your comment about the Group 3 brakes has indeed educated me.

The "spirit" of Pantera International is the sharing of information. Thanks to all who've chimed-in. I hope the comments keep coming.
Last edited by George P
At the time, no one had determined that using a larger diameter wheel (16,17,18)with the same exterior tire dimensions of the 15 inch tire would give greater cornering stiffness to the tire itself.

Widening the wheel was still considered the most you could do to gain cornering grip and maximum tire wall stiffness.

Therefore, the 8 inch rim with a 225-50-15 would generate better cornering g-force than the 7". Even with the exact same tire.

As the picture Ron posted (great pic Ron) indicates, the 225-50-15 tire fits so nicely within the stock fender without interference. Why fix something that ain't broken?

Even the fact that just the iron Girlings were used on the race cars indicates the car is not even in dire need of controlling the shocking more precisely by reducing unsprung weight?



These cars are really an outstanding example of how you can drive them daily on the street and take them racing on the weekends.

Much more so than even a Cobra is. If you get a little warm in the cabin during the race, turn on the a/c. A little bored waiting around for the flagman to call your group, turn on the stereo? No need to hide under the underpass if you get caught in the "rain"? In the Cobra? I don't think so. Big Grin

I personally purely by coincidence was able to do a side by side comparison of a 71 Pantera and a 427 s/c. Circa 1978.

The Pantera was by far easier to handle than the Cobra and with it's Weber equipped, high compression Boss 351, was notch per notch, as fast. The Pantera had Scheel seats in it, which for me made the cabin too confining...but it wasn't my car, so who could complain? Both were low EASY 12 SECOND 1/4 mile cars. I had to give each back unless I WANTED to get arrested AND have the cars confiscated as well.



What is the item in the illustration that looks like a Chiropractors spine display and the other rod that looks like a shift shaft component?
Last edited by panteradoug
quote:
Originally posted by JTpantera:
What is the item in the illustration that looks like a Chiropractors spine display and the other rod that looks like a shift shaft component?

Seat belts


I guess I wasn't expecting to see that? why would you show stock belt configuration here? I would expect competition shoulder harness and the aircraft type release seat belt.
George,

See the attached Invoice for my car it only mentions the rear 10" wheels ?

Doug,

I can confirm the goofy female end of the seat belt with the long stiff stem extending far above the plane of the seats .. is not on my std 73 Pantera ... but equip on my 79 GTS. Also the seat belt configuration lap and cross belt is different also and not recessed in the rocker but mtd more like a mustang with a std bolt.

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  • scan0001_(392x500)
I have a 5mm spacer, and I must have the spacers because the big Gr3 brakes, I can't put on the front rim without spacer, the rear rim have perhaps 1-1.5 mm clearance without spacer.

it is unable to put on stock spare wheel on a Gr3 Pantera with big Gr3 brakes.

There are more parts in the suspension which is unlike on stock Pantera brake and big Gr3 brakes.

The Gr3 safety belt was a Britax 4-point safety belt most likely made ​​by Sabelt in licence of Britax.

The charts is one of several performance parts, Gr3 parts was marked with * at part no. But not all Gr3 parts are in any of those two parts catalogs that I have.

The part catalogs is from ca 1975.

JTpantera Yes it seat belts but Not Gr3 seat belts.

It was possible to put on the Gr3 parts on "L", GTS, GT5, GT5S Pantera.

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