Ticking engine

[must89]

Hey everyone,
I have a problem with my 89 LX. It's got an L4 engine with an overhead camshaft. Recently it started to produce a terrible tick. It's definitely a tick and not a knock. It speeds up with my revs and slows down the same. I just changed my Camshaft and lifters/rocker guides and looked over/serviced my whole valvetrain. It can't be valves because I'd have a miss if they were sticking at all. My timing is fine. My oil is okay with no metal or anything in it (nothing out of the ordinary). I use 89 Octane fuel always and only from Chevron. I have run engine cleaner and fuel injector cleaner and oil additives and run it hot and cold and it still does the same thing. Right after changing the cam I started the car and it didn't tick for a moment. Then when I revved the engine a bit it came back (exactly same tick). Does anyone have any suggestions? I am completely dumbfounded.
Thanks