Hey
I think i know the answer to this one..
The alternator on my 90 has no resistance on the pully when you spin it. You can litterally spin it round with your fingers. There is also some play on the pully...
Its kicking out 13.7 at tickover, and 14 at about 2k rpm.
Im was thinking of getting a disco one for it anyhow.. Its like it reads this forum!