Where to buy correct alternator for a 1969 340 swinger non a/c car

I need some advice on where to buy the correct alternator for my non a/c 340 swinger. The original alternator is long gone. I have a stock wiring harness and a new old stock 69 voltage regulator. It seems like most of the aftermarket and rebuilt alternators available are much higher amp rating than my stock one should be.