Lower / Crank Pulley Differences?

[rakort]

Working on a big block, setting up my 68 RB / 440 no - AC engine accessory setup.

Wondering what is the difference in the application between these two lower pulleys.

Obviously the first will make the alternator and WP turn faster and the second won't.

Whats the thinking between these two different executions of the same function?

 

[Kern Dog]

There were a multitude of different pulleys used throughout the B/RB and LA series. A/C or not, P/S or not, Smog pump or not...Cars with the towing packages had HD cooling, faster moving fan with a smaller pulley...
Lots to sort through to get a working combination. It would be great if the pulleys were stamped with a visible part number but of the 50 or so I have here, only a few have any sort of ID marks.
A few months back I helped a guy find a set of correct pulleys for his Charger. It was a non A/C car that he was adding an aftermarket A/C setup and he wanted the stock type pulleys. I spent a few hours measuring, taking pictures, sending them, etc for him to get a correct set.
Good luck with the project.

 

[727]

If I remember right. The first pic with the bigger pulley will rub against the water pump pulley. The second pic looks like it may be the correct one. Next you will have to see if the bolt pattern is correct. I've wallowed out the one misaligned hole before and it worked fine

 

[Jeff_383]

1st one will def. hit the non-A/C water pump pulley. Not much room there between them