Alternator pulley larger size?

I have the bigger one on my 360..... cuz I like to shift it at 7000 whenever I have opportunity, but with 3.55s, and a 3.09 low; 7000=52mph. Then I hit the splitter and go again to 7000=66mph, Heck-Ya.
She's never had a problem keeping the battery pumped up,lol.