Roundback vs. Squareback alternators?

Newley rebuilt Round back 2.5 dia pulley
https://photos.app.goo.gl/Cpjcr3SzWekvi5Qq6
(And yes the engine is running)

Newly rebuilt Square back 2.75 dia pulley
https://photos.app.goo.gl/t6jbzbnnfiT3EB2p8