When you upgrade your existing alternator you never need to upgrade your 
voltage regulator. When upgrading to a high output alternator you rarely need 
to change your voltage regulator. The voltage regulator controls the alternators 
output by sending power to the rotor (field). The rotor spins inside of the stator,
the reaction between the two is how power is created. The voltage regulator 
senses the battery voltage, if the battery needs more power the voltage regulator 
sends power to the rotor coil causing it to become an electro magnet. If the 
regulator senses that the battery or system needs a lot of power it sends maximum 
voltage to the rotor making it a big electro magnet thus causing the alternator to 
produce maximum power. If the regulator senses a small need at the battery it will 
send minimal power to the rotor causing the alternator to produce little. Never 
does the alternators amperage go thought the voltage regulator. The area of 
concern when changing to a high output alternator is the amperage draw of the 
rotor. The voltage regulator does have a field amperage rating and because it 
has direct contact with the rotor you must be concerned with the amperage draw 
of the rotor. If the amperage draw of the rotor is greater than the rating for the 
voltage regulator the regulator will fail.

Randy