.120. You'll also have to machine the main accessory bracket that much, too, to get the alternator, a/c, p/s to line up. Also, if you're using the Duttweiler oil pump, you'll probably have to do a little grinding on that to clear the block. (No big deal)
A lot of guys endorse just using a .120 spacer behind the balancer, but I was concerned about cam sensor-to-cam gear alignment.