It can be done. It all depends on which alternator you have and how much amps you need. Some guys with older vehicles come into my work and have lower amp alternators and we rebuild there alternators with higher amp stators and rotors.
But the parts that are readily available only go so high amprage wise.
If you have a pic of your alternator or specs on your truck i can see what you could get out of it.
It'll only get so much before you will have to go aftermarket.
I think the guys name was Dominick
Tribal vision knows him and how to get a hold of him.
He has after market alternators that can produce LOTS of output.