About 15 years ago Honda used 4 - yes FOUR - man hours to build a car, exception was the NSX which took 40. Much of the labour is at suppliers who make up assemblies which are then fitted to the shell. This is the main eason why so many cars are now front wheel drive, the engine, suspension, drive shafts etc. is delivered as one piece and installed to the shell in minutes - difficult to do with rear drive - but Porche used to do it with the 928.
Doesn't answer the how long question - depends how fast the line runs - remember Charlie Chaplin in Modern Times!
Ian
2002 1.4 Petrol SE, silver with climate control for SWMBO, Honda Accord Tourer 2.2 iCDTi for me.