1972 MG B

Alright, here’s where things get a little tricky — the “1970’s MGB GT V8 Convertible” is actually a mash-up of two separate things, and the story is a bit of a puzzle.

Let’s untangle it step by step.

The MGB GT V8 — as it really existed

Introduced: 1973 by British Leyland (under the MG badge)

Type: MGB GT coupe (hardtop) with a factory-fitted aluminium Rover V8 engine

Why it happened:

MG had been watching private owners and small firms shoehorn V8 engines into MGBs for years.

The Rover 3.5-litre aluminium V8 (originally a Buick/Oldsmobile design from the early ’60s) was light, powerful, and compact enough to fit without ruining the car’s handling.

MG decided to make a factory version.

Performance:

Around 137–150 bhp depending on tune.

0–60 mph in about 7.7 seconds — pretty brisk for the early ’70s.

More relaxed high-speed cruising thanks to the torque.

Quirks:

Sold only as the GT coupe, never as a convertible from the factory.

The reason? MG feared that a soft-top with that much torque and speed might invite too much chassis flex (and, possibly, competition with the upcoming Triumph Stag convertible in British Leyland’s own lineup).

The MGB Roadster (convertible) — but without the V8 from factory

The MGB Roadster had been around since 1962 with a 1.8-litre B-series four-cylinder.

No factory V8 roadsters were made in the ’70s — although some prototypes existed.

However,… this is where history meets the enthusiasts’ workshop.

The “MGB GT V8 Convertible” — the unicorn that enthusiasts built

After the GT V8 launched, many MG fans wondered: “Why can’t we have this engine in a drop-top?”

Independent specialists and home mechanics began creating “what MG wouldn’t build” — V8-powered MGB roadsters.

Many conversions used the Rover 3.5 V8 (or later 3.9, 4.0, even 4.6 versions) and could be surprisingly well balanced thanks to the light weight of the alloy engine.

Some used official MG GT V8 parts for authenticity, while others went custom with upgraded brakes, cooling, and suspension.

These cars became something of a cult item — sometimes referred to as “MGB V8 Roadsters” or “MGB GT V8 Convertibles” in ads, even though that’s technically a contradiction in factory terms (a GT is a fixed-roof coupe).

Why no factory V8 roadster?

Internal politics: British Leyland didn’t want to overshadow the Triumph Stag (which was meant to be their V8 convertible).

US emissions laws: The V8 wasn’t easily compliant for the huge US market, which was vital to MG’s sales. The GT V8 wasn’t even sold in America.

Cost: Reengineering the roadster for the extra torque and safety requirements might have been more expensive than MG’s budget allowed.

In short:

The factory MGB GT V8 (1973–1976) was only ever a hardtop coupe.

A “1970’s MGB GT V8 Convertible” is either a private conversion, a kit-car variant, or a modern recreation of what enthusiasts wish MG had built.

The concept has a devoted following today — and many converted cars now have a value close to, or higher than, the original GT V8 coupes.

This Car

This outstanding MGB was rebuilt in 2016 to MGB-GT V8 specification. Tax Exempt.

Fitted with a Rover 3.5 litre V8 engine, a wonderful sounding four-barrel Holley downdraft carburettor and manifolding. V8 specification 4-Speed gearbox with overdrive on 4th and correct V8 rear axle ratio.

Custom-made Stainless-Steel twin-pipe exhaust system with RV8 exhaust manifolds. Upgraded V8 brakes and Brake Servo fitted. Electronic ignition.

Powder-coated GT-V8 style composite wheels with 185/70 R14 tyres. Uprated suspension with adjustable telescopic shock absorbers, front and rear, uprated coil-over front springs.

The body was stripped, fully refurbished and resprayed VW Flame Red. Bumpers removed, and “Sebring” style front and rear valances added.

New hood, tonneaus, carpets and interior trim panels. Seats recovered in cream leather; boot re-trimmed and carpeted. Telescopic struts on boot lid and bonnet.

Correct V8 speedo and rev counter; twin electric engine cooling fans with manual override switch. All lights LED; U.S specification, amber only front indicator lenses (very rare!).

Mileage is extremely low 5159 in the last nine years, as vehicle has only mainly been used for various Classic Car events since rebuild.

Great looking car with the correct specification and a great driving experience.