Humberstone Sports 408 – Hillman Imp based kit

1st January 1971 - Humberstone Sports 408 – Hillman Imp based kit

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The date given in the timeline is a guess based on the mention of the Humberstone Quartette that was displayed as a model at the 1970 Earls Court Motor Show.

The Humberstone Sports 408 is best described by, I believe, the leaflet that accompanied the pictures below. Chris Humberstone possibly at wheel?:

Chris Humberstone offers a design service. The 4O8 illustrated is one of many products of his very individual design work.

The 408 is an attractive 2+2 body featuring detachable gullwing doors, which are stored in the boot, when open-air motoring can be enjoyed. Re-fitting the doors takes only a minute, and besides being much quicker than a hood, they are watertight and permanent. Other features include retractable headlamps that cleverly provide daylight-flashing even when lowered, and a new type of built-in front aerofoil duct. The interior is in keeping with the rest of the design, being to a very high standard and of advanced, professional appearance. Full instrumentation is provided for, and four matching, luxurious, attractive seats and a leather-rim steering wheel are included in the kit, and all are specially designed for the 408. Detachable bumpers blend into the styling and are normally finished in a reflective colour.

All you need is a Hillman Imp floorpan and running gear. By purchasing a mechanically sound Imp (or Singer Chamois, Commer Imp Van or Sunbeam Imp), if possible with devaluing poor bodywork, it is possible to build a 408 in approximately 36 man hours, for less than £400. To ensure a continuing high standard of appearance of all 408’s built, all the difficult jobs are done at the manufacturing stage. Alloy wheels and wide tyres are supplied in the kit.

Work starts by bolting strengthening members inside the car. It is possible to still use the car with these fitted. Next, remove doors, disconnect eight items, and then cut the top of the body off just below the waistline. The new body then fits on to pre-drilled mountings on the strengthening members. Wipers, washers, heater and instruments are then re-fixed. The bonnet, boot, doors, glass, existing wheels and tyres, seats, trim, steering wheel, bumpers and roof etc. can then be sold, either for scrap or for spares. The ideal basis is a recent Imp Sport with a damaged roof.

The 408 is not just an Imp with a different body. It has been designed to provide a low drag factor, calculated at 0.31. The new body also reduces the weight of the car by nearly 3 cwt (road trim) thus raising the power to weight ratio by 20%. The combination of the low drag factor and low weight will dramatically improve the performance, and the response to Imp tuning will be even better. Also, the centre of gravity is lowered, and combined with the wider wheels and tyres, the already excellent road holding and Imp handling will be improved.

The whole character of the Imp with its race bred engine and responsive controls are ideally suited for the 408 project. Later, the 408 will be offered with its own chassis, and as a ***? car with *******? power *****?.

The manufacturing and marketing arrangements for the 408 have yet to be finalized. It is likely that another company will, by manufacturing rights acquired from us, be able to market the kit in September. Already, several firm orders have been placed, so a little delay is inevitable -but it will be worth waiting for – whoever makes it. The price of the finished kit will be around £250. Customer and trade enquiries should be directed to Chris Humberstone at the address below.

19 Evelyn Close, Egley Road, Woking, Surrey

Telephone: 67083

The leaflet also mentions Chris Humberstone offers:

Chris Humberstone will take on pretty well any type of interesting design work. He has facilities for Model-making, Artwork, Publicity, Promotion, Advertising, and he even offers a while-you-wait Instant Re-Print service.”