[6] He also felt that BMW did not have the capacity then to manufacture in quantity, but could make a smaller number of luxury cars with a higher profit margin per unit.

In early 1954, influenced by the public reaction to the Mercedes-Benz 300 SL and 220 S Coupé/Cabriolet show cars in New York in February 1954, the management of BMW approved the project.

[3] From 1957 all 503s were fitted with discs on the front as a result of recommendations from John Surtees[needs context] who had bought a 507.

[13] The perimeter chassis (so designed to keep driver and passengers safe in a collision) was constructed of sheet steel, as was the bulkhead, inner wings and some body bracing.

The bodywork, bonnet, doors and bootlid were made of aluminium/magnesium alloy, the original aluminium having found to be too soft on the prototypes.

It was intended that Baur should manufacture the bodies, and indeed they produced a prototype, but in the end they were hand built in house.

[citation needed] Despite some claims by owners and auction houses, no 503 bodies were either designed or built by Bertone.

Both cars used the 3.2 L version of the V8 engine developed for the 502, but with two carburettors and with an improved lubrication system using a chain-driven oil pump.

[3] Acceleration of the 503 in standard tune from standstill to 100 km/h (62 mph) has been estimated at 11–13 seconds since there are no reliable contemporary figures available; the top speed of the 503 is about 120 miles per hour (193 km/h).

The 503 did better amongst the upper levels of society in Europe, (particularly Germany and Switzerland) with many going to film stars (Curd Jürgens and others) Heads of State (e.g. Tito) and the nobility (e.g. Count Faber-Castell) and it won numerous gold medals in International shows at the time.