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Bob Edgeworth's 1972 MGB with Rover 3.5L V8

Bob Edgeworth · 1972 MGB Roadster

MG MGB

BritishV8: the site for enthusiasts of modified British sports carsBritish V8 Newsletter, Volume XI Issue 3, September 2003

Read the full write-up at BritishV8: the site for enthusiasts of modified British sports cars ↗

Photo: BritishV8: the site for enthusiasts of modified British sports cars

A 1972 MGB Roadster converted to Rover 3.5L V8 power

Bob Edgeworth fitted his MGB with a built 1981 Rover SD1 3.5L V8 and its matching five-speed gearbox, paired with a modified Ford 8-inch rear axle. The write-up is a dense spec sheet covering the engine build, fuel injection, cooling, brakes and suspension changes, useful for anyone planning a similar SD1-based V8 swap.

Specs

As stated in the original write-up.

Engine
1981 Rover SD1 3.5L V8, bored 0.030 inch, 10.5:1 compression pistons, balanced and blueprinted, Crower 50230 cam
Intake
Lucas air flow electronic fuel injection, cable throttle linkage, K&N air filter
Engine Electrical
Early model YM distributor reworked with transistorized ignition
Gearbox
Rover 5-speed from a Rover 3500 SD1, ratios 3.32/2.09/1.4/1/0.83
Clutch
Rover clutch and throw-out bearing, MG master cylinder, Triumph slave cylinder
Flywheel & Bellhousing
Rover items
Cooling
Aluminum V-belt Buick water pump, MGB V8 radiator, twin electric pusher fans from a 1977 MGB, adjustable thermostat set at 190F, 170F engine thermostat
Exhaust
RV8 headers into a pair of glass-pak mufflers, 2.25 inch pipes exiting ahead of rear wheels
Rear Axle
Ford 8 inch from a 1973 Maverick, 3:1 ratio, MGB outer housing tubes with re-splined Ford truck axles
Front Suspension
MGB V8 lower control arm bushings, 7/8 inch sway bar
Rear Suspension
Composite springs and traction bars
Brakes
Stock rear brakes, cross drilled front rotors, MGB V8 brake pads, stainless steel front brake hoses, silicon brake fluid
Wheels
6.5x15 Panasport wheels
Tyres
Michelin XSE 195/60/15
Interior
Stock
Body
Stock
Electrical
100 amp Motorola alternator, Weber gear reduction starter
Cost
$6500, all work done by owner except engine machine work
Completed
September 15, 2000, over 6000 trouble-free miles since

Parts used

Parts named as used in the original write-up, grouped the way the Parts page groups them. Where one of the shops we index lists the same thing for this car, it is shown underneath with a link to the shop.

Engine 3

Fuel & Ignition 3

Cooling 4

Gearbox & Drivetrain 6

Suspension & Steering 4

Brakes 4

Wheels & Tyres 2

Electrical 2

Other 2

  • RV8 headers

    Feed exhaust into a pair of glass-pak mufflers through 2.25 inch pipes

  • Glass-pak mufflers

    Pair fitted to the exhaust system exiting ahead of the rear wheels

Photos

3 pictures collected from the write-up, in the order they were posted, shown from BritishV8: the site for enthusiasts of modified British sports cars. A picture opens larger here, with the way through to the page it is on.

Bob Edgeworth's 1972 MGB with Rover 3.5L V8Photo: BritishV8: the site for enthusiasts of modified British sports cars
Federal Rover EFIPhoto: BritishV8: the site for enthusiasts of modified British sports cars
Donate Now!Photo: BritishV8: the site for enthusiasts of modified British sports cars

How it was done

Choosing the powertrain

Edgeworth built his MGB around a 1981 Rover SD1 3.5L V8, matched with the Rover 3500 SD1 five-speed gearbox, flywheel and bellhousing. He used a Rover clutch with an MG master cylinder and Triumph slave cylinder to connect it all to the MGB chassis.

Building the engine

The V8 was bored 0.030 inch and fitted with 10.5:1 compression pistons, then balanced and blueprinted. A Crower 50230 camshaft was installed, and the ignition side used a reworked early YM distributor with transistorized electronics.

Fuel and cooling systems

A Lucas air flow electronic fuel injection system was fitted with a cable throttle linkage and K&N filter. Cooling relies on an aluminum Buick water pump, an MGB V8 radiator and twin electric pusher fans sourced from a 1977 MGB, keeping the engine running cool.

Rear axle and suspension

A Ford 8 inch rear axle from a 1973 Maverick was adapted using MGB outer housing tubes and re-splined Ford truck axle shafts, set up with a 3:1 ratio. Rear suspension uses composite springs and traction bars, while the front retains MGB V8 bushings and a thicker sway bar.

Brakes, wheels and electrical

Front brakes got cross drilled rotors, MGB V8 pads and stainless steel hoses, running silicon fluid, while the rear brakes stayed stock. The car rolls on Panasport wheels with Michelin tyres, and electrical upgrades include a 100 amp Motorola alternator and Weber gear reduction starter.

Result

Completed in September 2000 for about $6500 with the owner doing all the work except engine machining, the car has since covered over 6000 trouble-free miles and reportedly returns 32 miles per gallon.

A summary in our own words. The full account, with all its detail, is in the original write-up: read it at BritishV8: the site for enthusiasts of modified British sports cars ↗

Worth knowing

  • Research the conversion thoroughly and consult someone who has already done one.
  • Adapting a Ford 8 inch axle with MGB tubes and re-splined Ford shafts gives a strong rear end.
  • Running twin thermostats, a 170F engine unit and a 190F fan switch, keeps the V8 from running hot.
  • Combining Rover, MG and Triumph clutch components can be made to work together with care.

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Bob Edgeworth's 1972 MGB with Rover 3.5L V8 | Restomod Life