Where to buy correct alternator for a 1969 340 swinger non a/c car

I like the way Rockauto's website works. Look it up by your application and all they have available wil be listed on the same page. I don't know the amp ratings for your car but it's probably a 46a. or there abouts. @Mattax can you help here?
Rockauto has 55 and 60 amp alts . some of them say may not come with pulleys or may be square back.