Austin-Healey 100/6 and 3000 buyer's guide

The six-cylinder Austin-Healeys are the cars most people mean when they say Big Healey. The 100/6 arrived in 1956 with the BMC C-Series straight six, and the 3000 followed in 1959 with a larger 2912cc engine and front disc brakes. The run ended with the BJ8 Mk3 in 1967. Bodies were made by Jensen, and from 1957 the cars were assembled at the MG works at Abingdon.

People buy them for the sound and pull of the big six, the long low shape and a strong rally history, and because specialists and clubs support them well. Most were exported, mainly to the United States, so many cars now in Britain are returned export cars, and a good number have been converted to right-hand drive.

This guide is for buyers looking at a 100/6 or 3000 at a dealer, privately or at an auction such as Mathewsons in North Yorkshire, and for owners preparing to sell. It does not cover repairs: where work is needed, a marque specialist can advise.

By Jon Cosson · Checked 20 October 2026

At a glance

Built	1956 to 1967: 100/6 from 1956 to 1959, 3000 from 1959 to 1967
Chassis types	100/6: BN4 (2+2) and BN6 (two-seater). 3000: BN7 (two-seater), BT7 (2+2), BJ7 and BJ8 (2+2 convertibles)
Numbers made	About 14,400 100/6s; the BJ8 Mk3 alone accounted for about 17,700 3000s
Body styles	Open two-seater and 2+2 with side screens to 1962; 2+2 convertible with wind-up windows from 1962
Construction	Ladder-type chassis frame with the steel body and floors welded to it; alloy bonnet and boot lid
Engines	BMC C-Series straight six: 2639cc in the 100/6, 2912cc in the 3000, about 124bhp in the first 3000 and about 150bhp in the BJ8
Gearbox	Four-speed manual without synchromesh on first, optional Laycock overdrive
Brakes	Drums all round on the 100/6; front discs and rear drums on every 3000, with a servo standard on the BJ8
Maker and factory	BMC; assembled at Longbridge, then at Abingdon from late 1957, with bodies by Jensen
Main market	Most cars were exported, the majority to North America
Clubs	The Austin Healey Club (UK), Austin-Healey Club USA

The Austin-Healey 100/6 and 3000 in brief

The 100/6 replaced the four-cylinder Austin-Healey 100 in 1956. It used the C-Series six from the Austin Westminster, a longer wheelbase and, at first, only the BN4 body with small occasional rear seats. A two-seat BN6 joined it in 1958 on the same longer wheelbase. Production moved from Longbridge to the MG factory at Abingdon in late 1957. All 100/6s have drum brakes on all four wheels.

The 3000 arrived in 1959. The engine grew to 2912cc, front disc brakes were fitted and the car was offered as the two-seat BN7 or the 2+2 BT7, now called the Mk1. Overdrive and wire wheels were options. Early cars have a side-mounted gear lever; a centre change arrived in 1961.

The Mk2 of 1961 had three SU carburettors and vertical slats in the grille. The triple-carburettor set-up is hard to keep balanced, and very few Mk2 BN7 two-seaters were made, about 355 in total. In 1962 BMC replaced the open cars with the BJ7, a 2+2 convertible with a curved windscreen, wind-up windows and a fold-down hood, back on two larger SUs. Enthusiasts often call it the Mk2A, although that was never an official name.

The Mk3, chassis type BJ8, was announced early in 1964. It had about 150bhp, larger SU carburettors, a walnut veneer dashboard, a revised exhaust and a brake servo as standard. The first cars, known as Phase 1, kept the earlier rear chassis. From May 1964 the Phase 2 car had reshaped chassis rails under the rear axle for more ground clearance, and radius arms in place of the Panhard rod. Separate indicator lamps followed in 1965. The BJ8 was the most numerous single 3000 type, at about 17,700 cars.

Production ended in 1967, as new American safety and emissions rules approached. BMC made running changes rather than model years, so the build date and chassis number tell you more than the year on the V5C.

Versions to know

Version	Years	What to know
100/6 BN4 (2+2)	1956 to 1959	The first six-cylinder car, 2639cc, with occasional rear seats, a longer wheelbase than the 100 and drum brakes all round. Overdrive was optional.
100/6 BN6 (two-seater)	1958 to 1959	Two-seat body on the same wheelbase as the BN4. It appeals to buyers who want a two-seater with the style of the earlier cars.
3000 Mk1 BN7 (two-seater) and BT7 (2+2)	1959 to 1961	2912cc, about 124bhp, twin SU carburettors and front disc brakes. Side screens and a separate hood frame. The BT7 2+2 is the more common.
3000 Mk2 BN7 and BT7	1961 to 1962	Triple SU carburettors and a vertically slatted grille. The centre-change gearbox arrived in this period. The BN7 two-seater is rare, at about 355 cars; check the identity carefully on any car offered as one.
3000 Mk2 BJ7 convertible (Mk2A)	1962 to 1964	2+2 convertible with curved windscreen, wind-up windows and fold-down hood, back to two larger SU carburettors. A brake servo was optional. Much better weather protection than earlier cars.
3000 Mk3 BJ8 Phase 1	Early 1964	About 150bhp, walnut veneer dashboard and standard servo, but the earlier rear chassis. The chassis number confirms which phase you have.
3000 Mk3 BJ8 Phase 2	May 1964 to 1967	Reshaped rear chassis rails for more ground clearance and axle travel, and radius arms in place of the Panhard rod. Separate indicator lamps from 1965. The most refined and most numerous 3000.
Right-hand drive conversions	Any year	Export cars, usually left-hand drive American cars, converted after returning to Britain. The chassis number keeps its L marking, so the car's origins stay on record. Ask who did the work and when.

Pros and cons

Pros	Cons
The C-Series six is a strong, unstressed engine with plenty of low-speed pull. Overdrive cars cruise comfortably on modern roads. Parts supply is strong on both sides of the Atlantic, with established specialists in Britain. Every 3000 has front disc brakes, and the BJ8 has a servo as standard. The BJ7 and BJ8 convertibles have wind-up windows and a fold-down hood, so they are far more usable in British weather than the earlier cars. A Heritage Certificate can confirm a car's original specification from factory records.	The body and floors are welded to the chassis, so serious rust makes repairs complex and costly. Ground clearance is low, especially before the BJ8 Phase 2, and the exhaust hangs underneath. First gear has no synchromesh and wears in time. The cockpit gets hot, and taller drivers can find the driving position tight. Many cars in Britain are returned export cars, often converted to right-hand drive, so history takes careful checking. Restoration costs can exceed the value of the finished car, so a cheap project is rarely a cheap car.

Pros

Cons

The C-Series six is a strong, unstressed engine with plenty of low-speed pull.
Overdrive cars cruise comfortably on modern roads.
Parts supply is strong on both sides of the Atlantic, with established specialists in Britain.
Every 3000 has front disc brakes, and the BJ8 has a servo as standard.
The BJ7 and BJ8 convertibles have wind-up windows and a fold-down hood, so they are far more usable in British weather than the earlier cars.
A Heritage Certificate can confirm a car's original specification from factory records.

The body and floors are welded to the chassis, so serious rust makes repairs complex and costly.
Ground clearance is low, especially before the BJ8 Phase 2, and the exhaust hangs underneath.
First gear has no synchromesh and wears in time.
The cockpit gets hot, and taller drivers can find the driving position tight.
Many cars in Britain are returned export cars, often converted to right-hand drive, so history takes careful checking.
Restoration costs can exceed the value of the finished car, so a cheap project is rarely a cheap car.

Myths and realities

Even panel gaps prove the car is straight.

Gaps on these cars were never tight, so the size of a gap matters less than whether it is even along its length and matches the other side. Uneven gaps can point to a sagging chassis, weak outriggers or a poor restoration.

A right-hand drive 3000 must be a UK home market car.

Many right-hand drive cars in Britain began life as left-hand drive export cars and were converted later. The chassis number and a Heritage Certificate will show what the car was when it left the factory.

An oil leak means the engine is worn out.

Leaks from the rocker cover and cylinder head joint are common. Oil pressure, smoke and noise matter more, along with whether a leak is heavy or from the crankshaft seals.

What to check

Chassis and structure

This is where most of your time should go. The steel body and floors are welded to the chassis frame, so the two have to be judged together. Take a torch, a magnet and a mat to lie on.

Main chassis rails: they can rot from the inside. Look for bubbling, fresh underseal hiding repairs, and patches welded over holes.
Front and rear outriggers that join the chassis to the sills: mud collects between them and the sills and eats both. Weak outriggers let the body sag.
Front and rear crossmembers: they are often used as jacking points and get dented by trolley jacks, which starts rust.
Sills and inner sills, which are structural. Check them from outside, from underneath and from inside the car with the carpets lifted.
Floors, footwells, the A posts behind the front wings and the B posts at the rear of the door openings.
Boot floor and the boot boxes where the rear springs mount, plus the spare wheel area.
Door gaps top and bottom, compared side to side. Gaps that change when the car is lifted at one corner suggest a weak structure.
On a BJ8, confirm Phase 1 or Phase 2 from the chassis number, and look for scrape damage to the rear chassis and the exhaust on earlier, lower cars.

Bodywork and panels

Most cars have been restored, some more than once. The aim is to judge the quality of that work as well as what rust remains.

Bottom few inches of the steel wings and doors, which rot from inside; use the magnet to find filler.
The joins where the alloy bonnet, boot lid and front shroud meet steel, where electrolytic corrosion blisters the paint.
The front shroud is made of alloy sections welded together and dents easily. Ripples, filler and cracked paint here are common.
Swage lines along the sides should line up across the wings and doors. A step at the door shuts is a sign of a poor restoration.
Chrome bumpers, grille and trim: replating and replacement are costly, so note what needs work.

Engine

The C-Series six is strong when it has been serviced. Ask for a cold start if you can, and look at the oil and coolant before the engine runs.

Oil pressure: a healthy engine typically shows about 50 to 60psi warm at 3000rpm on the move, with much lower readings at idle. Gauges can be inaccurate.
Blue smoke at start-up or under load points to worn bores or valve guides.
Oil and coolant leaks at the cylinder head joint and rocker cover are common. Heavy leaks from the front or rear crankshaft seals are more serious.
Overheating in traffic can come from silted waterways, a tired radiator or wrong ignition timing.
Carburettors: the Mk2's triple SUs are hard to balance, and some have been converted to twin carburettors. Note what is fitted against what the car should have.

Gearbox and drivetrain

The four-speed gearbox is strong, but it has known traits and most cars have overdrive to check.

First gear has no synchromesh. A loud whine or growl in first can mean worn or chipped teeth.
Early cars have the side-change gear lever; later ones have a centre change. Check that the type fitted matches the car's build.
Overdrive should engage in third and fourth with no more than a gentle bump, and disengage promptly. Slow or no engagement is often the solenoid or wiring; slipping under load suggests wear inside the unit.
Clunks when you accelerate or lift off can come from worn splines on wire wheel hubs, as well as from the propshaft and axle.
Rear axle: look for oil leaks at the hub seals, which can contaminate the rear brake linings, and listen for a whine that rises with speed.

Suspension, steering and brakes

Wear here often shows how well the car has been looked after, and modified suspension can change the car's character.

Kingpins: rock each front wheel top and bottom for play. Worn kingpins make the steering vague and can cause bump steer; they need regular greasing.
Steering box: a little free play at the rim is normal on this type of box, but excessive play, stiffness or leaks need investigating.
Ride height: a car sitting high at the rear may have new springs, which can take time to settle on a BJ8; a car sitting low may have tired springs. Phase 2 BJ8s sit a little higher at the rear by design.
Wire wheels: check for loose or broken spokes, worn or rusty hub splines and secure knock-on spinners.
Brakes: front calipers can seize and discs corrode on cars that are rarely used; rear wheel cylinders can weep and contaminate the shoes.
On a BJ8, or any car with a servo, check that the pedal drops slightly when the engine is started with the pedal held down. No movement suggests a failed servo.

Electrics and instruments

The electrics are simple, so most faults come from old wiring, poor earths and later additions.

Work every switch: lights, indicators, wipers, heater fan, horn and the overdrive switch.
Look behind the dashboard and in the engine bay for brittle wiring, scorched connectors and amateur additions. A new loom is a plus if it was fitted properly.
Ask whether the earth polarity has been changed or an alternator, electronic ignition or electric fan fitted, and that any change is recorded.
On a converted car, check that the instruments, switches and wiring have been moved neatly and that nothing has been left hanging behind the dash.

Interior and trim

Interiors are fairly simple and a good retrim makes a big difference, but missing parts can be costly to replace.

Check that the dashboard suits the car: early cars have a painted dash, the BJ8 has walnut veneer, which can be hard to source in good condition.
Cars from hot, dry American states may have sun damage to the dash top and seats.
Check for missing trim, side screens on early cars, the hood and tonneau, and the correct seats. Some reproduction trim kits fit poorly.
Hood: check the frame, fabric and rear window, which can degrade if the car has been stored with the hood folded.

Paperwork, identity and conversions

With so many export cars, restorations and conversions, the paperwork is part of the car. Read the numbers yourself rather than relying on an advert.

Find the chassis number plate on the bulkhead in the engine bay. The body number plate is usually nearby, so make sure you are reading the right one.
Read the chassis number prefix: BN4 or BN6 on a 100/6; BN7, BT7, BJ7 or BJ8 on a 3000, with an H in front on the 3000. An L in the number shows the car was built as left-hand drive.
Check the chassis number against the V5C and the engine number against the records.
A Heritage Certificate from the British Motor Industry Heritage Trust at Gaydon gives the factory record for the car, which typically includes chassis, engine and body numbers, build date and original colours. Austin-Healey records cover cars built at Longbridge and Abingdon from 1953 to 1971.
Check that the certificate matches the car's numbers. Forged certificates have been found, so if anything looks wrong, ask the Trust to confirm the record.
For a right-hand drive conversion, ask who did it, when, and for invoices and photographs. A neat conversion moves the steering, pedals and related parts properly rather than leaving brackets and holes behind.
Note modifications: alloy cylinder heads, five-speed gearboxes, uprated brakes, twin carburettor conversions on a Mk2, telescopic dampers. Some are welcome, but they should be declared.

On the test drive

Start from cold if you can, and watch for smoke and listen for rattles as the engine warms up.
Watch the oil pressure from cold, then again when warm, both at idle and at about 3000rpm on the move.
Pull away gently in first and listen for a growl or whine; change down to second and third to test the synchromesh.
Try overdrive in third and fourth: it should engage with a gentle bump and drop out promptly.
Feel the steering for wander, heaviness or excessive play, and see whether the car pulls to one side.
Brake firmly on a clear straight road. The car should stop straight, and on a servo car the pedal should feel assisted.

Buying at auction

Big Healeys appear regularly at UK classic auctions, including regional sales such as Mathewsons in North Yorkshire, and many are restored export cars. You will usually have less time with the car than in a private sale, so use the viewing days well.

What you can check in viewing week

Look underneath with a torch at the main chassis rails, outriggers, crossmembers, sills, floors and boot floor, ideally lying on a mat.
Use a magnet on the lower wings, door bottoms, sills and rear wing panels for filler, and look closely where alloy panels meet steel.
Find the chassis plate on the bulkhead and check the number and its prefix against the V5C and the catalogue; note whether it has an L for left-hand drive.
Lift the bonnet: check the oil and coolant, look for heavy leaks and amateur wiring.
Read every document in the history file, including any Heritage Certificate, restoration photographs and conversion invoices.
If start-ups are allowed, listen for smoke, rattles and bottom-end noise, and check the oil pressure gauge reads.

What you usually cannot do

You usually cannot drive the car, so the gearbox, overdrive, steering and brakes remain unknown.
You usually cannot put the car on a lift, so a full check of the chassis rails and outriggers is not possible.
You cannot remove trim or carpets to see inside the sills, footwells or boot boxes.
You often cannot run the engine long enough to judge oil pressure and cooling when hot.

Tips

Read the catalogue critically. Words like restored, rebuilt or matching numbers mean little without receipts, photographs and a Heritage Certificate. Look for what is not said, such as no mention of the chassis on a car described as fully restored.
Check whether the catalogue says the car is original right-hand drive or a conversion, and whether the chassis number agrees.
Remember the buyer's premium and any other fees on top of the hammer price, and read the terms before you bid.
Set your limit before the sale, including likely repairs, and stick to it. Do not get carried away by a rival bidder.
Arrange transport home before you bid. Do not assume a car bought without a drive is roadworthy, and check insurance and tax if you plan to drive it.

What makes one more desirable

Structural condition comes first: a car with documented chassis, outrigger and sill work is easier to sell than one with fresh paint and no evidence.
Later cars with wind-up windows, the BJ7 and especially the BJ8 Phase 2, are sought after for their usability and refinement.
Two-seaters are rarer than 2+2s and attract strong interest, especially the Mk2 BN7 and the 100/6 BN6.
Original right-hand drive cars are far fewer than export cars, so buyers place weight on a confirmed home market car. Conversions are widely accepted but judged on the quality of the work.
A Heritage Certificate that matches the car's chassis, engine and body numbers adds to buyer confidence.

This guide does not give values or predict prices.

Selling a Austin-Healey 100/6 and 3000

Buyers for these cars are often well informed and expect evidence. A well prepared car with a clear history and honest description stands out.

Preparing the car

Clean the car underneath as well as on top; buyers will look at the chassis rails, outriggers and sills with a torch.
Fix small faults that put buyers off, such as non-working overdrive, gauges or lights, using a specialist where needed.
Have the car serviced and the kingpins greased so it starts, idles and drives well.

Paperwork

V5C in your name with the correct chassis and engine details.
Heritage Certificate if you have one, or consider ordering one before you sell.
Receipts and photographs of restoration work, especially the chassis and body.
Invoices for any right-hand drive conversion, with the name of the business that did it and the date.
Old MOT certificates, service records and any import documents in date order.

Where to sell

Owners' club classified adverts, where buyers know the model.
Austin-Healey specialists, by sale or part exchange.
Classic car auctions, including regional sales such as Mathewsons, where the seller's commission and entry terms should be checked first.

Writing the description

State the chassis type (BN4, BN6, BN7, BT7, BJ7 or BJ8), Mk and Phase, engine, gearbox and whether overdrive is fitted.
Say clearly whether the car is original right-hand drive or a conversion, and where it was first delivered.
Be honest about structural work: say what was done, when and by whom.
Photograph the chassis, outriggers, sills, engine bay, chassis plate and interior as well as the outside.

Living with one

Parts supply is good for most mechanical and body parts, with established specialists in Britain and North America, though some trim and veneer items are harder to find.
Servicing is simple but frequent, including regular greasing of the kingpins and wire wheel splines, and attention to the carburettors.
The car is wide, low and heavy to steer at parking speeds, and the cockpit gets warm.
All these cars are more than 40 years old and can be eligible for historic vehicle tax. Cars that have not been substantially changed may be exempt from the MOT, but an annual check is still wise.
Classic insurance with an agreed value and limited mileage is widely available; tell the insurer about modifications and any right-hand drive conversion.

Clubs and registers

Questions people ask

Where do Austin-Healey 3000s rust?

The main chassis rails, front and rear outriggers, crossmembers, sills and inner sills, floors and footwells, A and B posts, the boot floor and boot boxes, and the bottom few inches of the steel wings and doors. Alloy panels corrode where they meet steel.

What is the difference between a BN7, BT7, BJ7 and BJ8?

The BN7 is the two-seat 3000 and the BT7 the 2+2, both with side screens, built as Mk1 and Mk2. The BJ7 is the 2+2 convertible of 1962 with wind-up windows, often called the Mk2A. The BJ8 is the Mk3 convertible of 1964 to 1967 with about 150bhp and a walnut dash.

Which Big Healey should I buy?

For touring in Britain, a BJ8 Phase 2 is the most refined, with the BJ7 close behind. Earlier two-seaters and the 100/6 suit buyers who prefer the original open style. Structure matters more than version.

Is a right-hand drive conversion a problem?

Not if it was done well and is declared. Many cars in Britain are converted export cars. Ask who did the work and when, and check the installation is neat. The chassis number and Heritage Certificate will still show left-hand drive.

What does a Heritage Certificate show?

It is a certified copy of the factory record held by the British Motor Industry Heritage Trust at Gaydon, typically showing chassis, engine and body numbers, build date and original colours. It helps confirm identity and originality, and should match the numbers on the car.

How do I tell if a 3000 was originally left-hand drive?

Look at the chassis number on the plate in the engine bay. Left-hand drive cars have an L in the number, for example HBJ8L rather than HBJ8. A Heritage Certificate will confirm the original specification.

Is an Austin-Healey 3000 a good first classic car?

It can be, if you buy a sound car and accept that it is heavy to drive and costly to restore. Have a marque specialist inspect the chassis and body on a lift before you buy, and join a club for advice.

Sources

Checked 20 October 2026.

An independent guide. Not a valuation and not financial advice. Always inspect a car in person or have it inspected before you buy.