If the cars Porsche builds go by project numbers starting way back in the fifties, aside from the number 550 what happened to the serveral hundred numbers between 365 and 901?

 

Some are contract projects for other manufacturers,
some are components (like the "915" gearbox)
and some are cars but never used in public (944 turbo, etc.,)

 

The 356 was actually the 349th project. The first one was bumped up so that Porsche's first customer wouldn't think they were the first.

Numbers that aren't on cars are typically parts or parts groups, like the transmissions (644, 741, 901, 915, etc)

Oh, and 356 production started in '48 with the aluminum bodied Gmund cars.

 

Very interesting question and one that is rarely answered. The best source to gain some insight into what happened between 365 and 901 is to read the two Ferry Porsche memoirs books. The one I am using to provide a small answer to your question is "Ferry Porsche Mein Leben". It does surprise me that these books are not more widely read in the Porsche community because they are soooo interesting and they have some great pictures as well.
What is important to know is that Ferry Porsche never refers to "Project numbers". He always refers to a Project and a Type number reference. I am not sure when Porsche Engineering sort of introduced the Auftragsnummer (Project) number as opposed to the original Porsche Type Number system. What we do know especially in the 9XX series is that some Project numbers were not used for the type number. An example: Project Number 942 was the RHD drive version of the 944, but the RHD type remained 944 and the parts were given a 942 prefix.
However back to numbers used between 356 and 901.
Post WW2 Porsche did a lot of work for companies such as Mercedes (Stirling Moss's Mercedes 300 SLR in 1955 had a Porsche gearbox), Ferrari, Alfa, Simca, BMW, the Indian Army and even the US Navy. Every one of these projects were given a Type Number. What they were I don't know. Porsche also did a huge amount of work for VW and Ferry Porsche did record these type numbers along with a development of the 356. I will just list some of what I have found.
Type 323 = Porsche Traktor (based on Porsche type 113).
Type 360 = Racing car "Cisitalia".
Type 519 = Porsche synchro gearbox.
Type 524 = Porsche 356 with mechanical fuel injection developed by Bosch.
Type 542 = 4-door Limo designed for Studebaker of South Bend Indiana.
Type 402 = A smaller version of the VW Beetle.
Type 534 = VW Beetle mixed with Porsche 356.
Type 597 = Porsche Military Jagdwagen.
Type 619 = 2-cylinder diesel motor (600cc) for VW.
Type 671 = Porsche synchro gearbox.
Type 672 = V6 motor.
Type 673 = 6-cylinder Boxer motor.
Type 675 = Small car design for VW (with Type 672 or 673 motors fitted).
Type 677 = Porsche synchro gearbox.
Type 702 = Motor for US Navy Gyrocopter.
Type 726 = 2-door Limousine design for VW.
Type 728 = Small car design for VW.
Type 7XX = Porsche luxury minivan or people carrier based on the VW Kombi.

Ciao,
Adrian.

PS: Karl Ludwigsen has lots more listed in his three volume book "Excellence was Expected".

 

That's interesting, thanks Adrian.

 

i beg to differ sir.

 

I think what he meant was the 944 Turbo isn't called the 951 to the general public.

Nice number of posts. (911)