MGB GT V8
1973-1976 / Coupe / United Kingdom
The MGB GT V8 was the factory-built version of what enthusiasts had been doing for years: fitting the lightweight Rover V8 into the MGB shell. The aluminium 3.5-litre V8 weighed barely more than the iron four-cylinder it replaced, so the car's balance was excellent. With 137hp and a wave of torque, it transformed the GT into a genuine 125mph grand tourer while actually improving fuel economy over the four-cylinder at highway speeds.
Only 2,591 were built, all in GT form, and none were officially exported to Australia. The handful that exist here were privately imported and are extremely valuable. The factory V8 is the holy grail for many MG enthusiasts, though the V8 conversion using aftermarket kits remains hugely popular in Australia and is a common club project. If you can't find or afford a factory car, a well-done conversion delivers essentially the same experience.
Thinking of buying a MGB GT V8?
What to look for, what to pay, what to avoid.
What to watch for.
Sill Corrosion (Inner and Outer)
Minor Body and Structure
Sill Corrosion (Inner and Outer)
MinorThe outer sill skin bubbles, softens, and eventually perforates. In advanced cases, the outer sill crumbles when prodded. The inner sill -- the structural member -- rots from inside the box section and loses its load-bearing capacity.
The sills are box-section steel with drain holes at the bottom. These holes block with dirt and underseal, trapping water inside the cavity. Corrosion works from inside out, so by the time you see exterior rust, the inner sill may be compromised. The sills are structural -- they carry bending loads and support the door hinges.
Replace both inner and outer sill sections. This requires stripping the car to bare metal in the sill area, cutting out the corroded metal, and welding new panels. Quality repair panels are readily available from Moss Motors, British Motor Heritage, and others. Cost: $1,500--3,000 per side for professional work. DIY is possible but requires competent welding skills.
Floor Pan Corrosion
Critical Body and Structure
Floor Pan Corrosion
CriticalSoft or perforated floor pans, particularly in the footwells and under the seats. Wet carpet is a telltale sign. In severe cases, you can see the road through the floor.
Water enters through deteriorated door seals, windscreen seals, and from below via road spray. Carpet retains moisture against the metal. The floor pans are thin and have minimal factory corrosion protection.
Repair sections are available for all floor areas. Weld in new metal. Cost: $500--1,500 per section depending on extent.
A-Post Corrosion
Minor Body and Structure
A-Post Corrosion
MinorRust at the base of the windscreen pillars where they meet the scuttle panel. This area can be invisible until advanced.
Water runs down the windscreen surround and collects at the base of the A-post. The double-skinned construction traps moisture.
Cut out and fabricate new sections. This is skilled work that requires correct jigging. Cost: $1,500--3,000 for professional repair.
Door Skin Corrosion
Minor Body and Structure
Door Skin Corrosion
MinorRust along the bottom edge of each door, working upward from the inside.
Drain holes in the door bottoms block, trapping water inside the door shell. The steel corrodes from inside out.
Replacement door skins are available. The skin is peeled off the frame, the frame is treated, and a new skin is crimped on. Cost: $300--600 per door.
Rear Spring Hanger Corrosion
Minor Body and Structure
Rear Spring Hanger Corrosion
MinorThe mounting points for the leaf spring rear suspension corrode, crack, or tear away from the body.
Road spray and mud accumulate around the spring hangers. The metal thins and weakens under the constant load of the spring.
New spring hanger assemblies are available. Weld in replacements. Cost: $300--800 per side.
Bottom End Bearing Wear
Critical Engine
Bottom End Bearing Wear
CriticalLow oil pressure at idle when warm (below 15 psi). A deep rumbling or knocking sound from the lower engine, particularly at idle and on acceleration. This is the main and big-end bearings wearing out.
Age and mileage. The B-series engine is tough but the white-metal bearings wear over 100,000+ km. Infrequent oil changes, overheating episodes, and oil starvation accelerate wear. The 3-main-bearing engines (1962--1964) are more susceptible.
Engine rebuild. The crankshaft is reground to the next undersize, new bearings are fitted, and the engine is reassembled with new gaskets and seals. Cost: $3,000--6,000 for a full rebuild.
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Common questions.
What is the difference between a chrome bumper and rubber bumper MGB?
The chrome bumper MGB (1962--1974) has slim chrome-plated steel bumpers, a lower ride height, and (in most markets) twin SU carburettors producing 95 horsepower. The rubber bumper MGB (1974.
Is the MGB Roadster or GT better?
It depends entirely on what you want. The Roadster is the quintessential British sports car experience -- wind in your hair, sun on your face, the sound of the engine bouncing off hedgerows.
Can I daily drive an MGB?
Yes, with realistic expectations. A well-maintained MGB is a reliable car by 1960s standards.
How bad is rust on an MGB?
The MGB is notorious for rust. The monocoque body has numerous water traps, double-skinned cavities, and poorly drained areas that corrode from the inside out.
Reference
Workshop Manuals
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