1970 Challenger 440 six pack alternator question

[750-h2]

Recently I was told by an individual that the proper alternator for my 1970 V code Challenger auto with A32package should be a 3438172 with a 3.2 inch OD double pulley. This fellow seemed extremely knowledgeable but I found this a little strange as the second pulley groove would remain empty? Can anyone confirm this? Thanks

[skdmark]

Do you have your broadcast sheet for your car?
I believe the Alternator is listed on Row 3. Under the header "ALT" what are the numbers?

Those numbers will indicate which alternator you were supposed to be equipped with.

For example:
I have a "72" on my broadcast sheet ('71, 383 N code, AT, power nothing)which indicates that my alternator should be part number 3438172

Same part number you mention and it is a single pulley

-Mark

[anlauto]

Part number is correct, but I've never seen a double groove pulley on a six pack

[750-h2]

So what size of single pulley came with the 3438172 alternator? 2.75 or 3 inch? I see on ebay right now there is a 3 inch single groove pulley for sale and the seller says its for a 440 six pack.

[AARTA340]

I seem to remember back in the day, when you would get a rebuilt one from Napa, my buddy who had worked there forever said they put the dual pulley on all of them, less parts to stock. I did buy one for a single and it had a double, not sure of the size though.

Part number is correct, but I've never seen a double groove pulley on a six pack