Lots of good comments... I'll just emphasize two. 1) With any upgraded alternator or even without its a good idea to beef the weak factory wiring in certain areas. Bypass the bulkhead connector with charge current in some fashion (many ways to do this) and upgrade charge wire size based on alternator you pick. A heavier charge wire is really important with single wire since the regulator cannot adjust for drops. 2) The upgraded squarebacks can make 100 amps or more running but idle output is not so hot (eg 50 amps). A newer style alternator and/or bigger case is needed to get good idle output.

Bigger drive pulleys, smaller alternator pulleys and higher belt speed can help at idle but no fun if high RPM damages the alternator or you throw a belt.