Silent13

[2002 SS Camaro V8 6-speed] I have a sound, really loud clicking sound that matches my revs. I've tried a quart Mystery Oil (as i was told). It's been 48 hours since then and i have almost no results. Also there is a chain-like sound comming from under the car (my guess was a throwout bearing), but it chimes on idle, when put in gear, and even louder up a hill. I know its not engines knocking because i solved that with octane booster (engine has a tune costs me expensive gas =P ). Could it be the whole clutch??. Anyone know about these two problems. If replacing the lifters is a must (because they are extremely loud) whats a rough price range for them and what else must be changed with 'em.

Thanks, Silent

my vehicle is also low-mid mileage 53k