Group 5 Racing - 1976-1981
The 1970s saw the introduction of new Group 5 regulations in GT racing that ultimately took the production based GT cars well beyond those of Group 4 and to what eventually became "prototypes" with just a vestige of the original shape and bodywork. This mercurial class of GT racing produced what were also known as the “silhouette cars”.
The Group 5 category was created by the CSI (predecessor to the FIA) for the 1976 World Championship of Makes. In the USA, the Group 5 regulations were mirrored by IMSA in the GTX category.
Dominating under these new regulations were the Porsche 935s, and the evolution of Group 5 and IMSA GTX cars can therefore be clearly seen through an examination of the Porsche 935s which started as a factory effort with a production based chassis in the 935/76 and eventually morphed into what were effectively full prototype tube-frame racers, keeping the roofline and windshield, but little else.
While this progression started with factory developed cars, it continued on with privateers, such as Kremer, Andial, Joest and others creating ever more extreme one-off versions. There were also fascinating efforts that brought BMWs, Fords, Ferraris, Lancias and others into the mix.
But ultimately, with the Porsche completely dominating Group 5 and IMSA GTX, and the cars bearing little resemblance to production cars, the GTP prototype class was spawned, launching initially with the 935s mixing is up with Lola T-600s in the same class … and even with a Pantera or two!
Today these epic cars continue on with the increasing popularity of historical racing events around the world.
Gr 5 Pantera (chassis number 2862) and Porsche 935 K3 are shown above at the HSR Classic Daytona 24 Hr event in 2014. The Pantera had just completed a pass on the Porsche! The Pantera pilots were ex-Formula One driver, Arturo Merzario along with Maurizio Micangeli, and Marco Micangeli. Signore Michangeli is one of the original drivers and team owners who raced two Gr5 Panteras in 1976-1981 and a significant contributor to the history of DeTomaso Pantera racing.
(Note: There are two Panteras stamped with chassis number "2862", one in Gr4 trim and a second car, pictured above, in Gr5 spec. The history and extensive pictures from the period, is documented in Philippe Olczyk's excellent book "DeTomaso - 'Macchine da Corsa', The Official Racing History". )
Here two Porsche 935s are ready to take to the track at Daytona 2015. The 935s underwent major changes over the years, starting with the factory 935/76, through various private efforts that took the Gr5 concept beyond those initial factory builds (as reflected by these two examples above).
The 935 on the left is the JLP-3 driven by John Paul Sr., and John Paul Jr. It was a full tube-frame car with bodywork similar to the Kremer K3. The 935 on the right shows an IMSA GTO classification - which became the new top GT "production based" class following the introduction of the GTP and Group C prototype classes.
Pictured above at the RM Auction in Monterey, the JLP-3 is known as the "winningest 935" with a total of 9 wins and 16 podiums for a 60 percent rate of podium finishes. It had its debut in 1981 and went on to win the 1982 IMSA Championship.
Less noteworthy for Porschephiles, but more significant for Pantera fans, may be the JLP-3's "encounter" with an IMSA GTX Pantera captured in pictures by then POCA member Matt Stone at the 1982 Times Grand Prix at Riverside Raceway (see photo towards the bottom of the page here).
A liberal interpretation of the rules regarding fender modifications in 1976 resulted in the slant nose 935 with the headlights now relocated below the bumper. In 1977 the body contour changed again with another creative interpretation of the rules, as the requirement for the rear window to remain in the production location can hardly be verified in the picture above. (Perhaps the Gr 5 Panteras could have taken a cue here from Porsche.)
With their total domination, the technical development of the Group 5 and IMSA GTX cars of that era is best encapsulated in the fascinating evolution of the Porsche 935 as the chassis adopted a tube-frame construction, the body became longer with more radical aerodynamics and the privateers continued the one-off revisions well into the GT prototype era.
The development of the Group 5 Panteras was a tiny fraction as compared with the Porsche 935s, but it still produced some of the most interesting and advanced Panteras of that time. It was a testament to the determination of a few individuals and their teams (most notably Hugh Kleinpeter in the USA and Maurizio Micangeli and Carlo Pietromarchi in Europe) who dared to take on the might of Porsche ... and that any Gr 5 / GTX Panteras existed at all!
More details on the original Gr 5 Panteras here.
Porsche 935, chassis 009 00030 raced alongside the Sala-Marverti Gr5 Pantera at the 1979 Le Mans 24 Hr, winning in the IMSA class. Shown here at the Monterey Historics. Photo: Gr5Pantera.com