From idle to about 2500 RPM there's an obnoxiously loud ticking that sounds like it's coming from the cylinder head, right under the valve cover. I'm thinking maybe a busted lifter, but i was hoping someone here might know for sure or have some other ideas.

 

I know this may be a dumb question but have you checked your oil level? What year is your car? The earlier models have normally noisy lifters. This is the best case scenario and only applies if this is not a "New Development" to your engine. To me it sounds as if your engine is not getting oil up there until your oil pump works hard enough @ 2500.

 

Yep I agree it sounds like a possible clogged oilway.