Concepts and Prototypes : Morris ADO77 (1973-1975)

The Morris Marina was conceived in a hurry, but its Designers consoled themselves in the fact that it was only going to last five or six years…

Here we reveal pictures of the ADO77, and discuss why it never came into fruition.

ADO77: The missing Marina

ADO77 body-in-white prototype shows how BL intended to extend the wheelbase and offer an exciting new body style.
ADO77 body-in-white prototype shows how BL intended to extend the wheelbase and offer an exciting new body style

The trouble with developing and launching a car in a hurry is that, even before it hits the roads, you’re already looking forwards to the not inconsiderable matter of its replacement. In the case of the Marina, its future was mapped out for it and, although it was a hastily conceived car, this was not so much of a problem as it would be significantly facelifted, and then replaced within six years.

And the Marina did perform reasonably well on the market, regularly featuring in the UK’s Top Five sellers. Buyers obviously liked its compact dimensions, commodious boot and lively performance. The Marina’s replacement cycle would come in two phases – the ADO73 facelift, followed by the ADO77 rebody.

But first: ADO73

Conceived shortly after the Marina’s launch in 1971, the ADO73 comprised a front-end facelift and an upgrading of equipment levels. No definitive ADO73 style has emerged from the archives but, looking at those pictured in the background of Allegro and ADO74 Styling Studio shots, no firm scheme had emerged. All of those that have been spotted singularly failed to improve on the elegant simplicity of Roy Haynes’ original.

Slated for a 1975 launch, the ADO73 came up against a number of obstacles in its development during 1972 and 1973 –  most notably the company’s deepening financial crisis and lack of resources. The launch was put back and, in the end, the ADO73 programme (which did see the new dashboard and trim improvements come on stream, illustrated below in these Vic Hammond sketches) was revised to exclude the front end facelift – ADO73, in effect, was the Marina Series Two, launched in 1975.

And on to the ADO77 Marina replacement

The ADO77 was already well under way in 1973. According to Graham Robson’s account of the boardroom machinations of the time, by as early as April of that year, the ADO77 would also form the basis of MGB and Midget replacements – a reprise of Project Condor’s role in the Marina development programme. The idea for ADO68 was fiendishly clever, and pretty much the brainchild of Roy Haynes, who proposed that the entire BL range could be served by five platforms, individually tailored to marque demands.

So a mid-sized MG could use the same platform of that of the Marina – and so forth. In 1968, this was radical stuff – and yet, Haynes was on the money with his plan. Today, it is standard industry practice. So, ADO77 existed from at least 1973, but what exactly was it?

BL had new engines and gearboxes on the way. The LT77 gearbox used in the Rover SD1 and Triumph TR7/TR8 was, in fact, a clever modular design. From it, a range of gearboxes could be produced, and the corporate plan was to produce it in ‘64mm’, ‘77mm’ and ‘88mm’ forms. In the end, only the ‘77mm’ gearbox was produced, but when the ADO77 was in development, it was pencilled in to use the smallest member of the gearbox family.

O-Series power leads the way

In terms of its engine, the O-Series was also well under way in 1973, and it was always a given that it would find its home in the ADO77. In fact, it was hoped to find service first in the ADO73 but, thanks to delays in the programme – a common theme in the company at the time, it missed its planned launch date spectacularly. But as ADO77 was also slipping, it was still planned to use the new OHC engine in the larger Marina replacement.

The ADO77 was also going to be considerably larger than the car it replaced. BL (and it wasn’t alone) had been been wrong-footed by Ford – because it hadn’t foreseen the Cortina’s growth from a 1200–1600cc car in Mk2 form to a 1300–2000cc car in Mk3 guise. Not only was the engine range larger, but the Cortina Mk3 grew considerably in size – and yet, because the market was buoyant and the country’s economy improving, buyers lapped up the bigger, more powerful car.

The Marina replacement would therefore grow to meet the Cortina’s challenge. The engine range would be pure ‘O’, in 1.7- and 2.0-litre form, and the wheelbase would grow from 93- to 100-inches in order to provide Cortina-rivalling room. It was also very useful to grow the Morris, as it was embarrassingly close to the Austin Allegro in terms of size and pricing – and, no matter how much BL denied it, the two cars were feeding off each other in the marketplace.

ADO77 interior rendering

Morris’s new car grows to fight Ford

The two cars pictured clearly show where the increase in size was going to come from – the wheelbase. And the top picture, shows that later in its programme, the ADO77 was going to employ much of the Marina’s body structure, but enlarged to suit. The signs are there to see – the wheelbase has grown (you can see the modified from wings and rear closing panels – look at the gap between the rear door and wheelarch), and the front becomes ‘lean back’ in aspect.

The most interesting aspect of the design is at the rear, where an interesting fusion of Coupé and saloon has been related. It is far from clear as to whether this was a final design solution, but it cannot be denied that it is remarkably effective, and it mirrors much of what Volkswagen was doing with the Passat hatchback at the time, although this is clearly still a four-door car.

In the end, the money ran out, and in a post-Ryder Report climate at BL, the decision was taken to merge the mid-sized Rover-Triumph project, SD2, with ADO77.

The end comes in 1975

This took place in September 1975, and the the resulting paper project, Triumph-Morris TM1, (a joint Morris/Rover–Triumph car, based on a cheaper Triumph SD2 platform and using the O-Series engine and LT77 gearbox) never got off the ground. The O-Series engines did make it into the Marina, in 1978, but no other aspect of ADO77 was carried over. When the Morris Ital came on stream in 1980, it retained the majority of the Marina’s body pressings, showing that panel changes were not really required to achieve a lean-back nose.

As for the ADO77, pictures of the completed car have yet to surface (presumably because it was never completed), but it seems a shame that Cowley’s Cortina never saw the light of day because, although AROnline’s readership once voted it the worst BMC-MGR ever, it really was guilty of no crime, other than living too long…

Top picture: BMIHT, bottom picture taken from the book ‘BL: The Truth About The Cars’ by Jeff Daniels…

Keith Adams


  1. Said this before in previous blogs. That lower photo of the ADO77 looked like it had potential back then. Better than a Marina with shades of Ford/Vauxhall modernity? It would be nice to see colour images of it but I guess none exist now. (if indeed they ever did)

  2. Every other project BL had on the books, including the Metro should have been postponed to bring this car to the market – Because it the car the market would have lapped up in the mid 70s. Would have been a doddle to Engineer with SD1/TR7 running gear and the O series. The internal politics of beards, horned rimmed spectacles and leather patches strikes again!

    • Agree but tide was changing fast in Europe in this segment: in 1978, new R18 and Peugeot 305 were competent fwd, once the Cavalier MK2 was out, only the “Triumph” -sporty- versions would have been relevant against that brand with a propeler series 316-320, though Fiat 131 and Taunus/Cortina-Sierra soldiered on, assuming that the suspension was derived from TR7/SD1 rather than 1948 Minor.
      A 1.5L would also have been needed, starting with 1.7 was ambitious…though its power wasn’t great, compared to the E 1,5L!
      This sedan is much better looking than the SD2, and once again BL persisted like for the 18-22 in keeping a fastback rather than hatch

      • Yes – But ADO77 should have rolled out in the mid 70s. The same time as the Mk4 Cortina/Taunus and Mk1 Cavalier. Then it would have been right on the money and potentially have generated the revenue and profits needed to engineer its eventual replacement with a FWD Cavalier etc fighter in the early 80s.
        By the way if the 4 door Marina Coupe styled car is shown here is considered to be ADO77, what is the car in the bottom picture taken from Jeff Daniels book?

  3. The top picture is a good looking car – far better than the SD2 protoypes for example. At this stage the whole package looks much like a Lancia Beta.

  4. So Ford engines were brewed by Heineken?

    “Not only was the engine range lager…”

    I like the mockup in metal.. looks kind of like they put the front end of a Charger Daytona/Firenza on it – could have looked quite good.

    I always liked the Coupe version, never was a fan of the other two..

  5. Unsure as to why “having the entire BL range served by five platforms, individually tailored to marque demands” is “fiendishly clever” ……..General Motors had been doing it for decades, including sedans, pickups and wagons and FIVE badges.

    Leyland should have head hunted someone from GM to guide them.

    • The 3rd light is much much shorter, might have looked “stubby/bloated” a la Allegro I’m afraid…
      The picture at the bottom is quite understated but quite elegant with a bit of Panther Rio on the front left side.

  6. Rather a shame as an updated Marina with O series engines, the new Rover transmission( with the option of five speeds) and better suspension could have done quite well as the original model was still selling well in 1975. Also a proper performance version of the Coupe with a two litre engine could have interested some Capri buyers. Instead the Marina was left to battle on until 1980 and was seriously outclassed.

  7. A typo in the article, the Marina’s wheelbase was 96-inches not 93-inches.

    It is interesting to compare the Marina with ADO71, the former proved to be too small instead of being ADO77-sized from the outset whereas the latter should have been Maxi-sized (like the Simca Alpine / Solara).

    How does the LT77 gearbox used in the SD1 and TR7/TR8 compare to the 5-speed Ford Type 9 transmission that seems to be a popular gearbox conversion for the Marina/Ital and others?

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