4 groove crank pulley
 

Finally getting to put all the accessories on and wondering why my 66 burb would have a 4 groove pulley. Water pump pulley is a 3 groove and both are early heavy cast pieces.

The alternator I pulled off was a 55 amp single groove, the burb does have A/C and factory closed PCV system and looks like a AIR injection delete as it was sold in NV. Being that it had a replacement 327 installed the AIR could have been removed at that time.

Since there is no spid or build sheet I cant tell if the original alternator was a 63 amp 2 groove set up.

Would there be 2 belts for the alternator, one for the AIR, and one for A/C? What other possibilities are there for 4 groove set up?

thanks