The hydraulically operated clutch was new as well, and an optional Laycock-de Normanville overdrive was offered with the standard four-speed gearbox, even an automatic transmission was available.

At the time Aston Martin had already started to consider a replacement for the Frank Feeley designed DB2 series of cars ultimately resulting in the DB4.

However, a quick update of the DB2/4 was also necessary and young designer John Turner, who was 17 at the time, suggested grafting the front of the DB3S onto the rear of the DB2/4.

Bentley-designed 2.9 L (2,922 cc; 178.3 cu in) Lagonda straight-6 engine, redesigned by Tadek Marek, was carried over from the DB2/4 Mark II predecessor.

A mid-level DBD option with triple SU 1.75" carbs and dual exhaust produced 180 hp (134 kW), and was fitted to 47 cars.

A high-output DBB engine with three twin-choke Weber 35 DCO 3 carburettors, special long duration camshafts, high compression 8.6:1 pistons and the dual-exhaust system was rated at 195 hp (145 kW) and ordered on just 10 cars.

All five Fixed Head Coupés were built close to the end of Mark III production and feature the mid-spec DBD engine.