How many AMP alternator for this application

Hey all,

Thanks in advance or any and all input on the following.

Just put a 318 LA in a 64 Dart. Im wondering what size AMP alternator will cover it:

HEI Conversion
2- 10" Electric fans
Will have a radio too , nothing fancy.
NO electric fuel pump or A/c

PS. We installed 6 gauge wire from the existing alternator
AND: We disconnected the ammeter and will install a voltmeter instead.

What do I REALLY need to sustain this application in AMP rating?

Thanks,
Mark