I'm getting my stock heads rebuilt, valve job and valve guides. This head is a stock 73 charger head. As far as I understand the compression on these things suck, 8.2:1
http://www.automobile-catalog.com/auta_details1.php

Would it be safe to mill a little off the heads to raise the compression and gain a bit of power on the cheap?

1973 Dodge Charger SE 400 automatic transmission. Curb weight: 3800 lbs. All stock so far. Goal: Reliable everday driveable warmed up 400 as close to 400hp as possible, then a 470 stroker if need be. Don't protect a feminist when the collapse comes!