Not exactly an answer to your question, but I thought I would run it past you:
Check out Ohio Generator: 1-330-875-6677 (im sure theyve got a website as well)and ask to speek to "Guss"
They have been around for decades, have alot of experience in audio-related alts, and custom build a majority of their alts. Guss in particular, as you talk to him, is a bottomless pit of information.
If it is a custom alt and a direct replacement is critical, they will find your exact alt, scrap the internals, and build an entirely new alt into the casing. No more worries about whether or not it will fit, and it is infinitely better than a simple "rewound" alternator.
Mine was custom and a real headache to build - cost about $450.
Hope that helps!