By Barry Lee Brisco
The 356 Fahrgestell Nr or "chassis number", also known (incorrectly) as the VIN*, can be found in three places on the car in its complete five or six digit form (partial numbers are found in other locations not described here). Photos of these three locations in a 1959 356A coupe are shown below. This is a Reutter-built car: 356s built by other coachbuilders may be different (see end of this article for more information).
Below: on the trunk floor just behind the spare tire strap loop (remove the spare tire and the rubber trunk mat to see it)
Below: next to "Fahrgestell Nr" in the upper right corner of the large aluminum plaque that is riveted to the trunk floor between the front right fender inner wall and the side of the gas tank. More information about the smaller "MODELL" plaque. These were only used in some 1959, 1960, and maybe 1961 cars.
Below: on the Karosserie (coachbuilder) plaque that is riveted to the driver side hinge plate cover which is only visible when the driver's door is open. "Kunstharzlack" translates as "synthetic varnish" (essentially, "paint") and "Farbton" means "color" (of the paint). For a list of 356 paint colors and numbers, see this page at www.stoddard.com. Some cars were delivered with no Farbton plaque, or they had a plaque but no paint code was stamped on it. It is not clear why this happened (it seems particularly common for 1958 cars) though sometimes it may have been because the car was painted a custom color and there was no code number for it. Of course if your paint code plaque is missing, maybe it was removed by a previous owner for a re-paint and never put back on.
There was one more location on some T5 and possibly all T6 cars: stamped vertically on the passenger side door pillar which is concealed by the aluminum cover plate. (Photo at right courtesy of Bruce Baker)
Besides the locations showing the complete chassis number, the last two or three digits of the number are typically stamped in several other locations, including the driver side hood hinge flange (first photo below), the upper left corner of the rain shield (second photo, John Chatley notes he has seen them in the middle and lower areas as well) and on the inside surface of each door (below). The upholstered door panel must be removed to see the numbers, which are either stamped or often written with a crayon (sometimes in yellow). If there are no numbers in those locations, either those parts are not original to the car or maybe someone just forgot to stamp them at the factory: it's not possible to say either with certainty.
Porsche contracted with Reutter to produce 356 bodies from 1950 to 1965, but also used other coachbuilders that may have stamped the partial chassis number in additional locations or fewer locations.
Drauz built the Convertible D and early T5 Roadster models and put the partial number in quite a few other locations, see this page for details. D'Iteren built the T5 and T6 Roadster model in the latter half of 1961. Karmann built the "Hardtop" coupe model in 1961 and 1962 and built coupes from 1962 until the end of 356 production. And Glaser built the earliest Cabriolets from 1950 through 1952.
* Technically, what is commonly called the "VIN" is really the Porsche chassis number, as the VIN system for auto identification did not come into use in the US until 1981. More information on the VIN system.