alternator mods

Hi fellow A body fans, I'm rounding up bits & pieces to install aftermarket AC in my 64 Valiant; I was going to use a March serpentine belt kit to install; I want to change an alternator from v-belt pulley to serpentine belt pulley.
Is there anyone producing a serpentine pulley to retro-fit the old style pulley? My alternator shop said it would have to be custom made since they are a pressed on fit. If not what alternator could use instead?

Thanks for any insight.