Boy after reading posts at other websites about ticking engines, I'm a little worried. Another owner of a 2003 Cobra had a ticking noise and this was the result: " My service ticket notes excessive cam bearing wear. I was told the reason for this is that the oil ducts through the left head are too small. and since the left head is toward the end of the oil route before re-entering the pan, the lubricated parts are "starved" for oil. The new head that was installed has improved oil duct design so that there should now be adequate oil supply to the lubricated parts on the left head." I have just over 1000 miles on my 2003 Cobra. At this point I have no ticking sound, my car was manufactured in December 2002. I changed the oil the first time at 800 miles and used the Ford blend 5-20w. I was planning on using the same oil at 3000 miles, then at 5000 miles going to Mobile 1 5-30w. So this is what I really need to know is if there will be a big difference in 5-20 or 5-30. I don't want to use the Ford blend since my understanding is that after a few years, the dino oils gum up the inside of the engine and synthetic doesn't, thanks, Doc.