Series 2a Alternator Upgrade

I have a standard alternator in my wagon, Series 2a 1966 petrol. I have an alternator from a Zaphira 120 amp output. Will there be any adverse effects to the wagon if I replace the old one with this new super powered one? I have several electrical extras added to the wagon which will draw quite a lot of current. I hope someone can help me.

all depends on amp ouput of new one and what ouput old one has. campare that to what additions u have added

Did the IIa have an alternator in '66?

Probably not but its had a n engine change to a 2.25 petrol from a series 3 I think.