<VV> one piece dual pulley?

[Ramon Rodriguez III]

This is one I could solve on my own with a little reading, but I figure
some of you can answer this off the top of your heads and I am presently
very busy.  We have here a dual pulley we are told is from a Corvair, but
it is all one piece.  I'm accustomed to seeing the add-on type that bolts
one pulley to the other.  What year/application etc. did the one piece dual
pulley come from?  Can this pulley be used on any year engine?

On the off chance that this is not the simple question I expect it is I can
provide photo's.

Thanks all!

-- 
Ray "Grymm" Rodriguez III
Lake Ariel, PA