60 amps are usually mounted up on the older carb'd engines, i looked up an alternator on the web and it says yours takes the 94 amp, i believe about the time when they strated switching over to higher amp alts because of the computer components, electric pumps and whatnot. More power needed.
I would remove your alternator and take it to a store that has the capability of checking it, also as i mentioned, have that battery checked out as well.