Best Alternator to give sufficient juice to the MSD 6AL ?

I don't think the 6AL takes up much juice at all. It's probably the blaster coil that sucks juice... Again like others have said. You need to get on the website and find out how many amps. It takes and how many amps you need. As far as headlights radios blinkers , you know all your electrical stuff and add that all up and see how many amps it is...
Remember as well that when it says a 100 amps, That's at full r p m's not at idle... Remember, a little bit of overkill on this is fine as it doesn't push the amps. It more gives the amps under the draw, as in it'll only use what it needs...
Also consider a good quality battery in combination with this as when you are at idol. And it's not putting out full amps. The battery is making up the difference and it will get recharged when you are up to full r p m...
My-2... other's WILL differ...