Alternator question

[Caberocks]

I want to replace the alternator on my 360 LA engine. The current alternator has 2 grooves in the pulley, but only one is used by the belt. Do I need a 2 groove pulley? Of was just what they happened to have at the time of installation? Curious why you would need 2 grooves on the pulley?

 

[DesertRat]

When I ordered a new alternator for my Barracuda it came with a double pulley. NAPA I think-------------

 

[Caberocks]

But why the double groove pulley if only one groove is used?

 

[TrailBeast]

But why the double groove pulley if only one groove is used?

There were originally single and double groove both, and the single was for non AC cars and the double for AC cars and everything else that used two belts. (like RV's)
It simplified inventory to carry only the double and use it for everything.

Singles are still around here and there.

 

[Caberocks]

Thanks Trailbeast! Was ordering one and can go either way.

 

[RPMagoo]

I recently purchased a rebuilt one, from NAPA, and it had a single groove pulley.

 

[TrailBeast]

I recently purchased a rebuilt one, from NAPA, and it had a single groove pulley.

Yep, around.