I got GREAT service from this guy a few years ago -- he even met me in Mystic CT on a Saturday night with the alternator I needed, for a cash deal. He saved at least three days of my vacation, and saved me a bunch of $ too. (Ever try to buy Volvo-Penta parts from a marina on a Saturday afternoon, while away on a vacation?). He even helped me with tech support on Sunday morning by phone. Very knowledgeable alternator/starter guy. I bought a Valeo(OEM) alternator for a little over $100 that would have been $600+ if painted green. Later I sent him my original fried alternator and he replaced the diodes for under $100, so now I have it as spare.

http://stores.ebay.com/buddasautomarineelectric