A total of 101,476[citation needed] units were marketed through the end of production in July 1962, the vast majority of which were exported.

A new chassis was designed with the side members further apart and the floor attached to the bottom rather than the top of the frame sections.

Falling sales of the traditional MG models caused a change of heart, and the car, initially to be called the UA-series, was brought back.

Rather than the originally intended XPAG unit, the car was fitted with the new straight-4 "BMC B series" engine from the MG Magnette saloon, coupled to a four-speed gearbox.

It used a high-compression (9.9:1 later 8.3:1) DOHC aluminium cylinder head version of the B-Series engine producing 108 hp (81 kW; 109 PS).

These wheels and chassis upgrades were used on a small number of the "DeLuxe" models built after Twin-Cam production came to a halt.

[6] Most of the problems with the engine were rectified with the introduction of a 100 bhp (75 kW; 101 PS) low-compression version,[7] but by then the reputation had been tarnished.

[8] Oddly, an open MGA Twin Cam (index PMO 326), road tested by The Autocar magazine in its 18 July 1958 edition only recorded a 0-60 time of 13.3secs with the standing quarter mile of 18.6secs.

An inset grille and Morris Mini tail lamps appearing horizontally below the deck lid were the most obvious visual changes.

Later, a new chassis was designed so as to seat the driver lower in the car with even cleaner bodywork resulting in the EX 175 prototype.

The later MG prototype EX 182 was very close to the final production MGA and was the car actually raced at Le Mans in 1955.

In Sports Car Club of America competition the MGA has won numerous regional and national championships.

Kent Prather has been the most successful American MGA driver to date with G Production wins at the SCCA national championships in 1986, 1990, 1995, 2002, 2003, and 2005.

In the United States, the MGA was used in NASCAR from 1960 to 1963 in the Grand National Series, failing to win a single race.