What's That Ticking?

Very simple test for rod knock: remove a plug lead. Start engine & listen for knock. Do the other 7 leads one at a time. If the noise goes or changes, that is the faulty cyl. Piston pin noise is usually a 'double tick'.
If the noise is still there after the above test, it is probably valve train. Lobe/lifter wiping or lifter pre-load.