Air condition pulley diameter/part number

[Sal Lubrano]

I am looking for a stock pulley for the 86 GN air condition compressor. Problem is I have no clue what the stock diameter pulley suppose to be. Does anyone know this information? There are so many different diameter six groove serpentine options.
There is 6580037 / 15-20038 installed now which has a diameter of 4.2''.
Some other info I have found.
6552402 4.9''
6580044 / 15-4519 5''
6580140 4.90''
6556717 5.5''
I believe it is one of these 3
6556715 4.6''
2724711 5.4''
6557503 5.42''

 

[pacecarta]

correct compressor is 15-20225 and from what i can find it has 5.00" pulley also listed as 4.97
id have to measure one to top/bottom groove to make sure they arent measuring based on the outer lip

 

[salvageV6]

I did a rough measurement of a 1987 pulley and it was 5" groove to groove. Jaws weren't wide enough on the calipers to get an accurate measurement.
Flat cable cut as close as possible to mate the ends on top of the grooves measured with a good rule then used pi.

 

[Sal Lubrano]

Perfect. Thank you both for the help.