From "MG, The A, B, and C" by Chris Harvey:
" . . . EX183 looked like a normal MGA but it had a tubular chassis like the popular sports cars of the day. Listers, Coopers and Tojeiros had managed to build particularly light cars with such chassis which went very well with MG power. EX186 was completely different: it had a near-standard MGA chassis modified only to accept de Dion rear suspension and support a body bearing a close resemblance to a Mercedes Benz 300SLR. It was smaller, but the lines were similar.
Both projects, which used Twin Cam engines, were killed by BMC because of their change of policy over sports car racing, but Thornley and Enever learned a lot from them. Thornley was to comment later that the tubular chassis idea would have cost too much and Enever decided he was not too keen on the de Dion rear suspension. At that time he considered it only a half-way house - 'in total weight it's heavier than independent rear suspension and it's still liable to tramp'.".

From "The Works MGs" by Mike Allison and Peter Browning
First Edition, Chapter 13, MGA-Racing page 212
"The team had already been working one or two special project cars for racing, including an MGA fitted with a de Dion rear suspension (EX 186), while one of the spare light-alloy MGA bodies had been built upon a tubular frame chassis (EX 183). These cars were to have had Twin Cam engines but, with the abandonment of the racing programme, both had to be shelved; EX 186 was sold to North America, while EX 183 was dismantled".

Notes from Peter Neal at MG Car Club – Kimber House, UK, 7 Jun 2012:
"The EX183 number relates specifically to a tubular space frame designed as a possible lighter alternative to the MGA chassis as used in the EX182 Le Mans cars in 1955. This frame was designed by Terry Mitchell around 1955/56. One example was made in the Abingdon Development Shop by Harold Wiggins and Brian Hillier. This was duly built up into a running chassis using MGA suspension etc. It was fitted with one of the lightweight bodies from one of the EX182 cars (I don’t know which one) and fitted with possibly a twin cam engine although there’s no way I can be sure of this at the moment. Terry had based his design on the space frames that were being produced at that time for racing cars (ie; Lotus, Cooper etc.). I’m sure that I’ve seen a photo of Terry’s frame in a book or publication somewhere, but I cannot recall where.
I don’t think this car was ever registered and would probably have been tried out on the road using trade plates. I recall going to Oxford in it one day with Denis Williams driving. My recollections of it are that it was extremely spartan inside, it was also extremely noisy and draughty. I remember having to clamber in with some difficulty as there was no door on the passenger side and the hood was up at the time. There wasn’t much opportunity to try out its performance on the local roads but it seemed to go quite well. Beyond that I’m afraid I can’t tell you much.
The idea was quickly dropped because John Thornley was rather nervous of producing anything that could be construed as being a racing car (he had strict instructions about this from on high). The car was eventually dismantled and the parts used elsewhere. The chassis frame was scrapped but I’ve no idea what happened to the body but I’m sure it would have been recycled.
“I’m pretty sure it was never raced but it may have been tested at MIRA or somewhere".

Here is a reference saying that EX-183 was fitted with a Twin Cam engine:


Build Sheet for EX-183: (click for larger 130-KB pdf)

Short mention in the book "MG: The Untold Story"

Excerpt from "MG: The Untold Story", in a list of EX- projects:
EX183 -- Experimental 1956 Le Mans car (tubular chassis) [27 drawings].