Austin-Healey 100/6 BN4
The Austin-Healey 100/6, introduced in 1956, replaced the four-cylinder 100 with a six-cylinder engine that would define the Big Healey character for the remainder of its production life. The BN4 designation identified the 2+2 version with occasional rear seats, the first Big Healey to offer more than two seats and representing a move toward greater practicality.
The BMC C-Series 2.6-litre inline-six engine initially produced a modest 102 horsepower, actually less powerful than the four-cylinder 100 it replaced. This was rectified in late production with a revised cylinder head that improved output significantly. The engine was smooth and tractable, with the linear power delivery characteristic of a well-designed six-cylinder that made the car an excellent long-distance tourer.
The BN4's 2+2 configuration added occasional rear seats that were suitable for children or very short journeys by adults. The rear seats folded flat to create a useful luggage shelf for touring. The body was essentially similar to the four-cylinder 100 but with a revised front grille and other detail changes.
Driving the 100/6 revealed a car of considerable charm. The straight-six engine was smoother than the four-cylinder predecessor, and the car felt more refined at cruising speeds. The handling was predictable if not sophisticated, with the live rear axle providing adequate grip in normal conditions. The steering was precise and well-weighted, and the disc front brakes provided reassuring stopping power.
The 100/6 was an important transitional model that bridged the gap between the original 100 and the definitive 3000. While sometimes overlooked in favor of both its predecessor and successor, the 100/6 was a capable and enjoyable sports car in its own right. The later examples with the improved cylinder head are particularly desirable.
Approximately 10,825 BN4 2+2 models were produced alongside the two-seat BN6. The 100/6 competed against the Triumph TR3A and MGA, offering a distinctive alternative with its smooth six-cylinder engine and the Healey's characterful driving experience.
Rust is the primary concern; check chassis rails, floor pans, rear shroud, and inner wings. The C-Series engine is robust but check for crankshaft wear and overheating history. Identify whether the car has the early or late cylinder head specification. Overdrive is essential for comfortable touring. Disc front brakes should be checked for caliper condition. Body panels are shared with other Big Healey models. Heritage certificates from the British Motor Industry Heritage Trust can verify original specification.
Produced at Longbridge from 1956 to 1959. The BN4 (2+2) was produced alongside the BN6 (two-seater). Early cars had a revised C-Series engine with lower output; later examples received improved cylinder heads. The 100/6 was succeeded by the 3000 with a larger displacement engine.