First series After World War II Morgan re-introduced their 4/4 model fitted with a 1267 cc
Standard engine. This continued in production until it was replaced by the larger Plus 4 announced at the 1950
Earl's Court Motor Show. The Plus 4 at its introduction was fitted with a 2088 cc
Standard Vanguard engine installed on a widened and strengthened 4/4 chassis with a wheelbase lengthened by . Hydraulic brakes, initially all drum, were fitted for the first time on a Morgan. In 1953 a higher performance version was announced with the 1991 cc,
straight-four engine as used in the
Triumph TR2 (a development of the Vanguard motor). The Vanguard engine continued to be available until late in 1956. Beginning in very late 1953, the radiator grille was now surrounded by a cowl that blended into the bonnet; initial cars received an interim version which only curved backwards at the top (nineteen examples were built of this design), followed by a transition version using the final cowled design which also curves backwards at the sides coupled with lower-mounted headlamps. The final design, with higher mounted headlight pods and the badge above the grille appeared sometime in 1954; flat radiator cars were frequently returned to the factory to have the front updated, along with various technical upgrades. Front disc brakes became an option in 1959 and were standardised in 1960. From 1956 the 1991 cc ,
Triumph TR3 engine was used and from 1962 the engine was the
Triumph TR4 unit, which increased displacement to 2138 cc. In 1963 a fibreglass bodied coupé called
Morgan +4+ was announced, but only 26 were built. Production of the Plus 4 ended in 1969, after supplies of the Triumph engine had dried up. A TR3 engined two seater car was tested by the British magazine
The Motor in 1958. It was found to have had a top speed of and could accelerate from 0- in 9.7 seconds. A fuel consumption of was recorded. The test car cost £1017 including taxes of £340. Following the success of the LawrenceTune modified example at Le Mans in 1962 a higher performance version, the Plus 4 Super Sports, was available from 1962 with a tuned engine and a "low-line" lightweight, aluminium body. Just over 100 were built. The then Swiss Morgan Importer, Rolf Wehrlin in Aesch/BL, developed a coupé version of the Morgan +4. To make up for the extra weight of the body, the engine was fitted with a Judson supercharger.
Second series In 1985, the +4 name was brought back on a version equipped with the 2-litre version of
Fiat's Twin Cam engine, coupled to the gearbox and clutch from the Plus 8. This model was only built until 1988, when it was replaced by
Rover's M16i unit and matching five-speed manual transmission. Still of two litres, power increased from . For export markets, a catalyzed version with was also on offer. In 1992, the +4 switched to using the wider chassis of the Plus 8, providing an additional of width in the cabin. At the same time, the M16 was replaced by the updated T16 engine. This specification remained until Plus Four production was again halted in 2000. The second series of the +4 underwent 114 design changes, including galvanising the steel chassis from 1995, while the steel wings were changed for
superformed aluminium units in 1998. While some changes were necessary to gain European Type Approval, others were dictated by customers, such as the addition of a long-door variant in 1997.
Third series In late 2004, the +4 returned, now powered by the Ford (Mazda) Duratec engine - again of two litres displacement. Power was at the time of introduction; later this was increased to . Production ended in 2020 in favour of the new CX-series
Morgan Plus Four. File:Morgan Plus 4 1991cc September 1951.JPG|1951 Morgan Plus 4 (flat radiator) File:1952 Morgan PlusFour DHC, Dutch licence registration 95-93-BL pic1.jpg|1952 Morgan +4 2-seater Drophead Coupé - early DHCs have twin spares at the rear File:1957 Morgan Plus 4 4-Seater in Cream, rear right.jpg|1957 Morgan +4 4-Seater File:1965 Morgan +4 4 passenger DHC (3828557715).jpg|1953 Morgan +4 4-passenger Drophead Coupé - this is the initial prototype from 1953, although it was retrofitted with the new rounded cowl in 1954 File:1967 Morgan +4 PUV 316F.jpg|1967 Morgan Car +4 (UK) File:'70 Morgan +4 (Hudson).JPG|1970 Morgan +4 (North America) File:1993 Morgan Plus 4 Roadster - exfordy.jpg|1993 Morgan Plus 4 Four Seater ==Competition use==