1956→1959 Austin-Healey 100-Six BN4

In August of 1956, the big-Healey entered regular production with a six-cylinder engine and included a pair of small occasional seats in the rear. Met with considerable criticism, it replaced the more powerful four-cylinder unit and was a heavier car.

Chassis prefix for the first cars were introduced as BN4 which denoted a 4-seat roadster. Later in production a BN6 variant of the 100-6 was introduced in March 1958 as a 2-seat roadster. This was more inline with the original 100-4’s concept and it outsold the BN4.

In 1957 a new cast-aluminum 6-port intake manifold was introduced to the model that replaced the integral head unit. With larger valves, and a higher compression power was raised from 101 to 117 bhp. It also increased the price from £762 to £817.

Roy Salvadori said “the new 6-port induction system gives her an impressive increase in punch, particularly in top from 50 to 80 mph….the Austin-Healey always had plenty of dig but now its outstanding…”

The first sixes were built at Austin’s facility at Longbridge until December 1957 when production resumed at Abington. The model was discontinued in Match of 1959, but some BN7 models, better known as the 3000 MKI, were produced with 100-6 badges.

Donald Healey was an avid racing enthusiast so the six-cylinder Healeys were almost immediately on the track. Three modified cars were entered for the 1957 12-Hours of Sebring with streamlined bodies and Weber carburetors. One of the cars finished second in class. Another attempt was made at the same race with disc-brake cars. That same year Corvette racer Dick Thompson agreed to race a 100-6 for the 1958 SCCA Championship which he won.

BMC’s Competition Department prepared UOC741 (BN4) TON792, PMO201, PMO202 and PMO203 for rally at events such as Liège-Rome-Liège, the Coupe des Alps and the Tulip Rally. They never won outright, but the results were always first or second in class.

In Detail

tags 3000, 100/6, six
submitted by Richard Owen
type Series Production Car
production years 1956 – 1959
built at Abington, England
price £/td> £817
engine Series C Straight-6
valvetrain OHV 2 Valves / Cyl
displacement 2639 cc / 161.04 in³
bore 79.4 mm / 3.125 in
stroke 88.9 mm / 3.5 in
compression 8.7:1
power 87.2 kw / 117 bhp @ 4700 rpm
specific output 44.33 bhp per litre
bhp/weight 106.17 bhp per tonne
torque 192.5 nm / 142 ft lbs @ 2400 rpm
body / frame Steel Body over Steel Frame
driven wheels Front Engine / RWD
front tires 5.9-10
rear tires 5.9-10
front brakes Discs
rear brakes Drums
curb weight 1102 kg / 2429 lbs
wheelbase 2337 mm / 92.0 in
front track 1328 mm / 52.3 in
rear track 1270 mm / 50.0 in
length 4001 mm / 157.5 in
width 1537 mm / 60.5 in
height 1270 mm / 50.0 in
transmission 4-Speed Manual w/Overdrive
gear ratios 2.93:1, 2.05:1, 1.31:1, 1.00:1
top speed ~185.1 kph / 115.0 mph
0 – 60 mph ~10.7 seconds
0 – 100 mph ~36.0 seconds
0 – 1/4 mile ~17.0 seconds

Auction Sales History

1956→1959 Austin-Healey 100-Six BN4

1957 Austin-Healey 100-6 BN4-LO/36204

As documented by its British Motor Industry Heritage Trust Certificate, this 1957 100-6 BN4 Roadster was built on 1 March 1957, and it was delivered new, with wire wheels, a laminated windscreen, a heater, and overdrive, to an Austin-Healey dealership in New York City. The car remained in the United States for its whole life, until it was recently purchased by an individual residing in the United Kingdom.

Auction Source: 2014 Paris by RM Auctions

1956→1959 Austin-Healey 100-Six BN4

1957 Austin-Healey 100-6

The Austin Healey 100/6 was introduced in late 1956 as a replacement for the very popular 100/4 series. The new Healey was powered be an in-line six rated at 102 horsepower. It also had a longer wheelbase, revised front end and a new interior layout with 2 small rear seats
– This particular BN4 is a remarkably original and well optioned example
– Believed to be under 30,000 actual miles
– Original paint, interior, soft top, top boot and tonneau cover
– Car comes with radio, heater and a factory hardtop with original paint

Auction Source: 2010 Mecum at Monterey