alternator issues

[bubblerboy64]

The alternator is generating some rattling noises which I am assuming
are from bearings. My questions are two. Is this something that needs
immediate attention? Two, are these alternators an over the counter
item at the local NAPA store or can I expect problems locating and
finding? This is for the 3208NA engine. I am tempted to tackle this
myself. I don't have a swing out radiator but it would appear to me
that I can reach in from either behind or over top the radiator and get
to this. But before I started I thought perhaps I would ask for any
information relative to what I might encounter. If I would have to pull
the radiator I likely would pass on the project. I know the belts are
involved but it would appear that there is room to work. I realize its
a little difficult not being able to look at my exact situation but any
info would be appreciated. Even if its a don't do it.
John Heckman
central Pa
1973 FC converted to diesel.