Yesterday, I've noticed this coarse, grinding-rattle coming from the passenger side of the motor...You can even feel it, coming through my alternator..I took the belt off(thinking it was an alternator bearing or something), but the noise is still there...I spun the motor to a constant 1500rpm, and the noise faded away...Any clues?? The motor has a little over 8k miles on it...

 

Water pump?? Or possible starter hanging? If you are running headers check all the bolts a leakk can make some pretty weird noise.

 

Yea, the waterpump is what we're starting to figure....Could be the bearings inside, or the input shaft hoppin' teeth...something along those lines..But, ya never know..