What is this sound?
 

I tried to upload a video but I failed. The sound comes from the passenger side of the engine. Its a very pronounced ticking that seems to match engine RPMs and grows louder when revved and then quiets down on its own, This is the only time it doesn't seem to match RPMs. What is this? Perhaps a sound that was unnoticed before?

Time to cut open an oil filter if you have not done so yet. Might as well rule out simple things though... Inspect for exhaust leaks.

I discovered the source, its came from a blown exhaust manifold gasket. I may need stronger ones. It just crumbled away. Suggestions?

A stock Metal MLS Gasket.

I'm with him^

You can't beat stock.