First, you really shouldn't care about your post count. Just post meaningful, informative things and you will get a custom title in a fairly short amount of time.
Second, posts in chit-chat don't count towards your official post count.
Third, the number of posts needed can be found in
http://www.chiefdelphi.com/forums/sh...hreadid=14078, or in the official faq:
http://www.chiefdelphi.com/forums/mi...=faq&page=1#7.
Fourth, Brandon always has the final say in whether or not you get the title. If you spam the boards, post nonsense, etc it could take much, much longer than normal.
--Rob