Jowett through Lawrence Pomeroy of The Motor joined forces with ERA and they persuaded Professor Dr Ing Eberan-Eberhorst, formerly with Auto Union, to come to England. He joined ERA in Dunstable and, amongst other projected development and chassis work, designed and developed what became the Jupiter's tubular steel chassis. The suspension used soft torsion bars and anti-roll bars front and rear with independent suspension at the front. The engine was mounted very far forward ahead of the front axle line with the radiator low behind it over the gearbox. Adjustment of the anti-roll bars easily influenced oversteer and understeer to provide fine suspension tuning. On this torsionally stiff frame Reg Korner of Jowett put a steel framed aluminium drophead coupé body with a bench seat for three people. Eberan's chassis had been designed for a closed coupé and it proved to require strengthening. The anti-roll bars were abandoned. There was no external access to the boot (trunk) and the bonnet (hood) was rear hinged and opened complete with the wings. These cars were only for export, it was hoped coachbuilders would supply the local market.
An initial 75 chassis were supplied to external coachbuilders such as Stabilimenti Farina, Ghia Suisse, Abbott of Farnham and others in Britain. The high cost of these, mostly handsome, bodies for what was only a 1500 c.c. car obliged Jowett to build their own complete cars. The Jowett factory made 731 Mk1 and 94 Mk1a cars. The Mk 1a came out in late 1952 with a little more power (63 bhp) and an opening lid to a boot of larger capacity.
The flat four overhead valve engine of 1486 cc was more highly tuned than in the Javelin and had its compression ratio raised from 7.2:1 to 8.0:1 developing 60 bhp (45 kW) at 4500 rpm giving the car a maximum speed of 85 mph (137 km/h) and a 0-50 mph time of 11.7 seconds. Two Zenith carburettors were fitted. A four speed gearbox with column change was used.
Source: Wikipedia, 2014; Mecum Auctions as part of the Anaheim event in November, 2014.