Page 1 of 2 Next >> Marcos co-founder Jem Marsh saw a great opportunity to field a purpose-built racer at Le Mans when the regulations changed dramatically ahead of the 1968 season. Gone were the big-banger sports racers, replaced by a new Group 6 class with a three-litre displacement limit, matching the contemporary Formula 1 regulations. This allowed Marsh to literally cut a few corners by acquiring F1 suspension components, an engine and a gearbox to help create the mid-engined Marcos Mantis XP (experimental prototype).
Designing the Mantis XP was entrusted to an in-house team headed by brothers Dennis and Peter Adams. Upholding a Marcos tradition, the Mantis XP featured a central monocoque constructed from plywood. Fitted to both ends of the stress-bearing tub were steel subframes. Added to this purpose-built chassis were Cooper suspension components, used on the 1967 T81 Formula 1 cars. The front consisted of lower wishbones and top rockers with in-board springs and dampers. The rear was also familiar with lower wishbones, top links and trailing arms.
Marsh had originally intended to fit the Mantis XP with a BRM V12 engine, which, although also used in Formula 1, had been designed specifically to power Group 6 prototypes. After it proved too expensive, Marsh turned to Jack Brabham instead and acquired one of his team's successful Repco V8s. This Australian-built engine combined a Buick production block combined with purpose-built heads with a single overhead camshaft. Detuned for longevity, it still produced well over 300 bhp. As in the Brabham BT24, the Repco Type 740 was mated to a Hewland DG300 five-speed manual gearbox.
With the exception perhaps of the plywood centre section, the Mantis XP had a very conventional chassis. The same could certainly not be said of the very angular exterior design. To cheat the wind on the long Mulsanne straight at Le Mans, the car featured a very long and low nose. The low cockpit featured an abundance of glass all around with the doors completely crafted from Perspex. Providing a stark contrast with the nose, the Kamm-tail was cut-off immediately behind the rear wheels. Period reports suggested the car tipped scales at just 650 kg. Page 1 of 2 Next >>