I am trying to buy a set of C5R heads and have come across two sets forsale. One set has 005 on it and the other has 009. What is the difference between the two casting numbers? Apparently the 005 is an older version? I have a C5R block that I will be using these with.

 

009 is PN 12480090 Is the CNC casting with a 30cc chamber to start with
005 is PN 12480005 Which is the standard C5R casting with a 38cc chamber to start with

Bret