911 numbering?
 

can anyone shed some light on why Porsche chose to number different 911s such as 964,993 so on.....I understand these numbers where technically internal numbering, just curious if anyone k nows the story

Wiki is your friend.....
Porsche 911 - Wikipedia, the free encyclopedia

The short story is that when a new project came up they gave it another number in the 900 series. The 964 must have been such a big change that it got it's own project number.

But clearly, all 900 numbered cars are not 911 variants. There is a list of all the projects/cars in the 900 series out there. It is pretty remarkable. A handful of the 900 numbers are not used.

Edit - I just found this text and I stole it word for word:

The remaining numbers 9xx were basically set aside for Porsche car models, either sports or race cars. Resulting in 912, 930, 914, 916, 917, 924, 944, 928, 964, 986, 996, etc, etc, etc. These still seem sequential to a large extent through at least 964 or so. I don't know if Porsche has publicly said what their plans would be when they run out of 9xx numbers, but there are probably a bunch of gaps (they may actually have used up the 9xx project numbers internally by now, but not as public model numbers) and Porsche has also become more sparing in the use of those numbers. For example 986/996 and 987/997 have been used for over 10 years despite a bunch of model variations, which were almost certainly different projects.

More data

http://stasher.us/porsche_type_list.htm

The new 918 is a bit of a retro step! But it is a spiritual successor to the 917 I spose.

I believe the 991/998 will succeed 997 btw