With an eye on the potentially lucrative US market, Marcos contrived a longer-wheelbase Mantis with 2+2 seating in a closed coupe style and the Triumph 2498cc six-cylinder engine. Initially this engine was launched in European TR6 tune, complete with Lucas fuel injection, but fitting the "federalized" version of this power unit for North American sale would have made sense. An overdrive gearbox is standard, with Borg Warner automatic transmission promised for the future.
The car's basis is a square-section steel tube chassis frame, clothed in the GRP coupe body, and though the details are different the front and rear suspension designs are like those of the smaller two-seater Marcos models, the front end being from the Triumph Vitesse, the rear axle from the Ford Capri 3-litre.

Marcos established dealerships in the USA but cars didn't sell and it was effectively total loss financially.
The company moved to new premises in Westbury, Wiltshire.

MARCOS MANTIS
£3,185 (incl. P.T.)
First new Marcos from the equally new factory at Westbury in Wiltshire, the Mantis takes its name from the earlier racing coupe from the same company. The exciting two-door saloon is a generous 2+2 with above-average space for rear seat occupants, and a light and airy interior. The front-mounted power-unit is a fuel-injected Triumph six-cylinder as fitted to the TR6. The 150 h.p. engine gives the Mantis a very high performance, but it provides a low noise level also. The live rear axle is positively located by an 'A' bracket. There is a 10 cub. ft. capacity for luggage.
London Show review