Series in detail
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1st series instruments in Bracco's 1951 Mille Miglia car, unrestored
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1st s. Instruments, but a special finish
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2nd s. instruments
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early 4th s., similar but different from 2nd s.
The B20 Coupes are recognized as being in 6 different series. Detail differences in the body and instruments include: 

Body
  • 1st series have grilles with a hole for a starting crank, and aluminum bumpers with rubber strips. The bumpers were then changed for chromed steel.
  • 1st and 2nd series had sloped headlights like the sedans, and tail fins. Later cars had a more refined and smooth rear design, with larger rear windows. 
  • 1st and 2nd series have smaller trunk areas, but no negative back pressure (exhaust) like the later cars
  • early series (1st and 2nd for sure) have ducted intake air ducted from in front of the radiator. Later cars let air in from vents that open in the firewall
  • 1st through 3rd series had a large aluminum floor panel in the trunk for lightness, deleted in the later cars. 
  • 1st through 3rd series had  heavier rolled rims for wheels.
  • 1st through 3rd series dashboard  (up to the change of instruments in 4th series) is  about 30mm further forward. 
  • 4th series only had tinted windows. 
  • 6th series had vent windows and taller interior space. Typically the 6th series cars had a chrome strip down the bonnet, and different hub cabs and wheel covers.
  • LHD only from the 4th series on. 

​Instruments
  • 1st series instruments same as from the Berlina.
  • 2nd to the middle of the 4th series instruments were  grey plastic, with counter-rotating rev counter. Slight difference between 2nd and 3rd series.
  • 4th series instruments changes to lovely white on black Jaeger instruments, shared w/ Ferraris.
  • 5th and 6th series instruments are white needle on black Jaeger similar to Flaminias. 
  • 6th series dashboards were painted in with two-tone color schemes, and featured a chrome trim strip.