Take a look at http://www.holley.com/data/Products/.../199R10243.pdf.
I had a B&M blower on a street car and it started sounding different I found the teflon strips deteriorating. May not be your problem but easy enough to check out.
I heard some noise's yesterday-while kicking the shit out of the ol mans jet boat I went back and noticed oil on the blower drive and i need to look at it - was pretty warm to the touch !
Take a look at http://www.holley.com/data/Products/.../199R10243.pdf.
I had a B&M blower on a street car and it started sounding different I found the teflon strips deteriorating. May not be your problem but easy enough to check out.
I had the front seal behind the drive pulley go bad and had oil all over the blower.If that happens the front bearing runs dry and gets hot.