"underdrive" pulley?

I'm building a street/strip big block and need some help.

I've eliminated my mechanical water pump and gone electric, no power steering or any other pulleys...just crank and alternator.

My question is this: what can I pull a "smaller" pulley from to drive my alternator? I don't want to buy an aftermarket aluminum one just something that's going to spin me fast enough to keep me charged.

I realize the most common reply will be to "go to the local scrapyard and start looking"....well that's fine and all but I'm sure this isn't the first time that somebody has done this.

As always...THANKS
Author: 66cornet