Easy way to tell if U have a K26/8.
 

I've just uncovered this info:

If you have a K26/8, the AUSF # on the tag will end in either 7041 or 7042.

where did you get this info from? and has it been independently confirmed?

1. Some other site, 2. No

I suppose a compressor housing w/tag off of a #8 could also have been put on a #6 turbine (and visa-versa).

My original K26 was a 7042. I upgraded to a 7006 (K27) compressor on the #8 hot side.

Here is some "some" confirmation, which I found on THIS site:

http://forums.pelicanparts.com/porsche-924-944-968-used-parts-sale-wanted/521969-wtb-26-8-turbo-compressor-wheel.html

Here is the link to where I saw the original info:

Specs on kkk k26/8 :: motorgeek.com

Look at post #17, in the thread.

The "confirmation" link also suggests that k26/6's were either 6710, or 6720

Let me add that since these parts are mixable and matchable, the only way to tell for sure, is to look at the # (6 or 8) that is stamped on the outside (and inside) of the turbine housing, near the inlet.