I'm pretty sure your car was carbed from the factory right?? (With the external voltage regulator on the inner fender). I did a high amp alternator conversion from Alterstart (Ebay)... The alternator cost about 125 bucks, then 25 for the wiring kit from them. It was a bolt on install (althought I DID have to enlargen the bottom bolt hole with a drill bit), and was a One wire deal. Only thing.. it wasn't a 3G alternator.. It was a 2G design, with the external fan, but 150 amps.
Edit: They no longer sell this alternator.. now they sell a 3G with 160 amps for 170 + 18 shipping. Good deal if you ask me! Check it out...
http://cgi.ebay.com/ebaymotors/65-8...cmdZViewItemQQcategoryZ33573QQitemZ7996890669
Nick