Here's a link on Oil filter's from marc haibeck's site. I was looking for original Delco black filters to put on my car because I couldn't stand the new Delco blue color on the LT5. After reading this I quickly changed my mind about the OEM Delco black filter.
http://www.zr1specialist.com/HAT%20W...comparison.htm
I currently run the Mobil 1 or Bosch. I like the Bosch because it is also black and with a little work to take off the labeling it looks just like the original Delco in black.