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Stephen Blackburn's 1971 MGB with Chevy 283cid V8

Stephen Blackburn · 1971 MG MGB

MG MGB

BritishV8: the site for enthusiasts of modified British sports carsas published in BritishV8 Magazine, Volume XIX Issue I, December 2011

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 1971 MGB rebuilt with a Chevy 283 V8 and custom frame

Stephen Blackburn converted his long-owned 1971 MGB into a V8-powered sports car, fabricating a full custom frame and suspension after the original unibody floors proved too damaged to save. The project ran from 2003 to 2011 and blends a blueprinted small block Chevy, a T5 five-speed, and a double A-arm/4-link chassis with Wilwood brakes. It is worth reading for the scratch-built chassis work and the owner's candid notes on what he learned along the way.

Specs

As stated in the original write-up.

Engine
Chevy 283 cid small block, rebuilt and blueprinted; 358 hp at 6400 rpm and 322 ft-lb at 4900 rpm at the flywheel; steel crank, dome top pistons, I-beam rods, Comp Cams solid lifters and roller rockers, custom 202 aluminum heads
Fuel & Ignition
Edelbrock Performer intake, Holley 650 double-pumper carburetor, Pertronix Flame Thrower distributor and coil, Pertronix 8mm plug wires
Cooling
Be Cool aluminum radiator with two 10 inch pusher fans and two 8 inch puller fans
Exhaust
Custom four-into-one headers into 3 inch side pipes; also a 2-into-1 oval 2.5 inch system with Spin Tech muffler
Transmission
Borg Warner T5 (0.67 final drive) with Lakewood bellhousing, McLeod pressure plate and hydraulic throw-out bearing, Tilton master cylinder with remote reservoir, custom driveshaft
Rear End
Stock MGB axle, 3.909:1 gears, open differential
Front Suspension
Custom double A-arm setup with Aldan coilovers, tubular crossmember replacing stock subframe
Rear Suspension
Triangulated 4-link with Aldan coilovers, stock MGB axle
Brakes
Wilwood master cylinders with remote reservoir; front 4-piston aluminum calipers with 11.25 inch vented discs; rear single piston calipers with integrated E-brake and 10.75 inch vented discs
Wheels
Stock MGB disk wheel centers on 15x7 inch rims with baby moon hubcaps
Tyres
Firestone Firehawk 205/55R15
Electrical
Rewired from scratch with relays, power windows, 600 watt stereo, Nippondenso 60 amp mini alternator, Optima Red Top battery
Instruments
Stock MGB oil, water and fuel gauges; Auto Meter Designer Black speedometer and tachometer
Weight
Approximately 100 lb lighter than stock despite the added frame, due to floor and suspension changes

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 5

Cooling 1

  • Be Cool aluminum radiatorBe Cool

    Fitted with two 10 inch pusher fans and two 8 inch puller fans for V8 cooling

    In the shops
    Aluminum Radiator ↗Moss Motors – Triumph TR6/TR250· $355.00 USD
    Aluminum Radiator ↗Moss Motors – Triumph TR6/TR250· $358.50 USD
    Aluminum Radiator ↗Moss Motors – Triumph TR6/TR250· $364.00 USD

Gearbox & Drivetrain 5

Suspension & Steering 3

  • Custom double A-arm front suspension

    Fabricated to replace the stock front end, mounted on a new tubular crossmember

  • Aldan coiloversAldan

    Used front and rear on the custom suspension

  • Triangulated 4-link rear suspension

    Located the stock MGB axle on the new frame

    In the shops
    Five Link Rear Suspension Kit ↗Moss Motors – Triumph TR6/TR250· $3,154.95 USD
    Trunnion, Suspension Link ↗Moss Motors – Triumph TR6/TR250· $66.50 USD

Brakes 3

Wheels & Tyres 2

Interior 2

Electrical 3

Other 3

  • Custom four-into-one headers

    Feed into 3 inch side pipes; wrapped in header wrap

  • 3 inch side pipe exhaust

    Pictured exhaust routing from the custom headers

  • 2-into-1 oval 2.5 inch exhaust systemSpin Tech

    Alternate exhaust setup with a Spin Tech muffler

Photos

36 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.

Stephen Blackburn's 1971 MGB with Chevy 283cid V8Photo: BritishV8: the site for enthusiasts of modified British sports cars
Chevy 283 small block engine, rebuilt and blueprinted.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Be Cool aluminum radiator with two 10 inch pusher fans and two 8 inch puller fans.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Nippondenso 60 amp mini alternator.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Custom four into one headers feed into three inch side pipes.Photo: BritishV8: the site for enthusiasts of modified British sports cars
This little Chevy engine is rated 358 hp at 6400rpm and 322 ft-lb at 4900rpm (at the flywheel).Photo: BritishV8: the site for enthusiasts of modified British sports cars
Edelbrock Performer intake manifold. Holley 650 double-pumper carburetor.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Custom 202 aluminum cylinder heads. Note spacers under the valve covers.Photo: BritishV8: the site for enthusiasts of modified British sports cars
4-piston aluminum calipers with 11.25 inch vented disks.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Old school: header wrap over mild steel headers.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Custom wiring with eight fuses where once there were four. (Note also heat shrink tubing.)Photo: BritishV8: the site for enthusiasts of modified British sports cars
Photo: BritishV8: the site for enthusiasts of modified British sports cars
Brake plumbing for Wilwood master cylinders with remote reservoirs, and steering shaft routing.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Beautifully detailed engine compartment.Photo: BritishV8: the site for enthusiasts of modified British sports cars
When the stripe is offset to the side like this, some of us call it a Sebring stripe.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Mechanically stripping all that paint was obviously a lot of hard work!Photo: BritishV8: the site for enthusiasts of modified British sports cars
Custom designed and fabricated double A-arm front suspension with Aldan coilovers.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Original MGB front crossmember deleted in lieu of lightweight tubular structure.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Completely new frame for what was once a unibody car.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Custom front and rear suspension.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Triangulated 4-link rear suspension featuring Aldan coilovers. Stock MGB axle.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Single piston calipers with integrated E-brake and 10.75 vented disks.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Fabric seat covers.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Custom interior trim details.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Remodeled Abingdon pillow style dashboard with its padding deleted.Photo: BritishV8: the site for enthusiasts of modified British sports cars
New floorboards.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Trunk paint.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Stock MGB disk wheel centers mounted on 15x7 rims. Baby moon hubcaps.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Mark one taillights on a mark two MGB.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Checking bumper fit.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Bumper over-riders will be deleted.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Ready for glazing.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Ready for primer.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Epoxy primer.Photo: BritishV8: the site for enthusiasts of modified British sports cars
Stripes before color.Photo: 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

A long-deferred project

Blackburn had owned the MGB since high school in the mid-1980s and always wanted to build it into a V8 car, but lacked the funds until he began the conversion in 2003. The car had damage on the passenger side front and rear, which shaped the direction of the rebuild.

Building a frame from a unibody

Because of the existing damage, he cut out the floors and the front half of the unibody and fabricated a complete custom frame to carry the new suspension, deleting the factory front crossmember and subframe in favor of a lightweight tubular structure.

Engine and drivetrain

A Chevy 283 small block was rebuilt and blueprinted with forged internals, solid lifters, roller rockers and custom aluminum heads, feeding through an Edelbrock intake and Holley carburetor. Power goes through a Borg Warner T5 five-speed, McLeod clutch components, and a custom driveshaft to the stock MGB rear axle.

Suspension and brakes

Custom double A-arm front suspension and a triangulated 4-link rear, both using Aldan coilovers, were fitted to the new frame. Wilwood master cylinders and multi-piston calipers with vented discs front and rear handle stopping duty.

Testing while unfinished

Blackburn drove the car off and on through the build, mainly to test the suspension, even while it still had its original four-cylinder engine, before the V8 and remaining systems were completed.

Body, interior and electrics

The body was stripped, epoxy primed and painted with an offset Sebring stripe, bumpers re-chromed and over-riders deleted. Inside, the dashboard padding was removed for an Abingdon pillow look, new floorboards and fabric seat covers were fitted, and the car was rewired from scratch with added fuses and relays.

Completion and reflection

The car was finished on 31 July 2011 with 900 miles logged by early October, and Blackburn considers it still a work in progress. His only regret is waiting so long to start, and he credits other owners' build write-ups for ideas he used.

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

  • Do not wait decades to start a build you have long planned, as time and funds will always be a factor.
  • A cracked bellhousing led to switching to a stronger Lakewood steel unit for durability.
  • Converting a unibody car to V8 power may require a full custom frame rather than partial reinforcement.
  • Testing the chassis and suspension early, even with the original engine, helped validate the setup before the V8 went in.
  • Learning from other owners' published project write-ups can save time and inform design choices.

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Stephen Blackburn's 1971 MGB with Chevy 283cid V8 | Restomod Life