If you use the wrong pulley config, you will also have a slight mis-alignment. It will work, but is not right. It may cause excessive wear on the belt or possibly throw it at high rpm.
The proper non-A/C set up is for a single groove alternator pulley and single groove water pump pulley.
We bought our alternator and pulley set up from Mancini Racing.
Here are some pictures of the set up for my son's engine for his 71 Valiant. We converted from A/C to non....