[Big Kev-O]

If you are running a stock alternator with a regulator I would ditch it for an internally regulated CS or SI style alternator. If you don't want to change the alternator pulley on a CS style alt you can opt for the a 61amp 10SI or 12SI if you need more amps. We can't tell you if the 61 amp alternator is sufficient with out knowing the fans amp draw. I would leave the factory 12ga. alternator wire in place and then run an "alternator bypass" wire from the alternator to the large battery wire post on the starter. This would eliminate the need to mess with the factory splice or upgrade the fusible link.

I'm assuming you plan to run this fan with it's own relay.