The Plus Four is the second model, after the Plus Six, to be developed on Morgan's new bonded aluminium "CX-Generation" platform but, like its predecessor, it is assembled with an ash timber frame. It is powered by an original BMW TwinPower petrol engine producing and of torque when combined with the 6-speed manual transmission and of torque with the 8-speed automatic transmission.
Morgan announced that after the Plus Four would be sold at the company's twelve United States dealerships for the 2025 model year. Under a federal 'replica car' rule via the Fixing America's Surface Transportation Act, sales will be limited to 325 cars per year in order to legally circumvent federal safety regulations, although the vehicle would still have to comply with lighting and emissions regulations. Only the automatic transmission will be available for US buyers, as the manual will require a different calibration to meet California Air Resources Boardemission standards. The Plus Four will not be available in Canada due to homologation rules.