Difference between 1967 and 1973 alternator on Small block?

I have a 1973 340. I got the 70 and later water pump and crank pulleys. I have the 1970 and later alternator bracket with 1967 318 alternator. The alternator and crank pulleys line up, but the alternator not so much. Is there a difference in the alternator mount or pulley on a post 70 small block as opposed to the 69 and below? It looks like if I had a double pulley the outside pulley would probably line up. Thank you.