Angle milling removes more material from the head surface towards the intake...raises compression but also straightens the air path into the engine.
Mopar small blocks have 18 degree heads. By angle milling you can lower that number a couple degrees. In my dirt world 9 to 13 degrees is the ticket.
Man, thanks for that! I have to find a way to make some accurate measurements. My gearhead friend is coming over today, I'm hoping to go over my options with him. The input from this thread helps immeasurably.