Hello
The Porsche order number: 900.074.037.02. says:
900 = regular normpart
999 = modified normpart ( Porsche only )
The .02 shows the revision or say the part is not the same like the 00 but a direkt replacment.
The descriptions is:
Hexagon bolt M8x35 DIN 931-8G Gal Zn9.
Now DIN stands for Deutsche Industrie Norm and was the german counterpart to SAE, BSP or BSA yet DIN isn´t direkt existing anymore as ISO took over. But DIN and ISO run parrallele as long still DIN parts are in existance.
M descripes Metric Standard Thread in form and tolerance M according to DIN 4579.
8 is the nominal Diameter
35 is the nominal lenght. On DIN 931 parts the length is without head.
DIN - 931 ( today ISO 4014 )stands for the Parts descrition. 931 is a hexagonal head bolt with partial threat on the shaft ( DIN 933 is same screw but threads up to the Head )
-8G is old for 8.8 witch gives the strenght from the bolt. ( In SAE you would have a pentagon or five star head ). This is descriped in DIN 20484.
Gal Zn9 is galvanic zinc coatet according to DIN 50960. The coating is minimal 0,009 mm on the worst spot ( corners & edges ).
The DIN 931 changed over the years. One example is that the spannersize went down from 15 mm to 14mm in 2WW and in mid 60´s to 13mm. Since 5 years the 12mmm head would be effective.
http://www.din.de/
DIN parts Searchengine :
http://www.boellhoff.de/D/aktuell/index.html
http://wueko.wuerth.com/
http://www.berner.de/www/html/home/home_index.html
Grüsse,
Roland