January 1969 saw the introduction of the Marcos 3 Litre wooden chassis.

The 1600 chassis was adapted to take the relatively compact all new Ford Zodiac 3 Litre V6 engine and gearbox. This raised the power to 136 BHP with a top speed of 125 mph, and acceleration from 0 - 60 in 7.5 seconds. The introduction of the 3 Litre engine also saw major improvements to several areas of the car including electric windows, totally new doors and door frames, a power bulge to house the twin choke down draft carburettor, padded dashboard and rocker switches, and single rectangular headlamps.

The 5 1/2 J x 13 Marcos cast alloy wheel was introduced with the 3 Litre model. The Marcos 3 Litre proved a very capable rival to the 4.2 Litre E-Type Jaguar with over 115 being built at Greenland Mills, Bradford on Avon.