Just a quick update from my previous posts.
I installed the EBay Alternator (85 AMPS advertised) I mentioned in my previous post and it fits like a glove as there is no difference in size at all.
The only issue I had was I had to turn the case about 1 inch so the capacitor would clear the frame. Unfortunately I didn't disconnect the battery before hand so I blew the 55 AMP fuse so am waiting for one to come in.
I also found this link giving info regarding the old GL1500 GW and what Alternator it had. Apparently its alternator will also fit the Valkyrie is listed cheaper.
http://www.rattlebars.com/valkfaq/Steve