Alternator Sizing - Amp requirements

I'm trying to decide on an alternator for my big block 66 Dart project. I'm thinking a toyota Denso 90 amp should work, but what do you guys think? I'll be running an electric fuel pump, Taurus cooling fan, MSD ignition, line lock, head/tail lights, etc.

I know the right way to figure this out is to add up the amp draw and size the alternator accordingly, but how do I know how much power a particular alternator produces at idle?

Any idea if a 90 amp alternator would get it done for me? Thanks guys. This electrical stuff is like black magic to me.
90 amp alternator wont cut it for a street driven car with all that load. Its idle and low rpm cruzn that will hurt you.
Will 90 amp do it, maybe.
Will you run the guts out of making it run hot, yes.
IMHO I would find a single wire of 140 amp that turns on at the lowest rpm.
This is one case you dont want to scrimp on.