I too have the 85 amp alternator, but 65 would be fine unless you are planning a monster stereo. And if you are planning a monster stereo, I highly recommend you fuse and wire the stereo and amp separately from the existing wiring. The wiring in our cars was not scaled to the power requirements of even 1980s stereo units, let alone newer stuff. I know this because the prior owner of my car tapped into the left side light wiring circuit for a stereo, swapped in a 40 amp fuse for the 5 amp fuse, and melted the fuse block, wiring behind the fuse block, wiring behind both the front and rear running lights and the left tail light housing.