I wouldn't angle mill unless you are a guy with lots of time and can do machine work yourself, and you like to fool around with stuff. Angle milling was primarily a Chevy thing, because the 23-degree heads make the chamber really deep. This was about the only way to pull the volume down for compression, especially on some of the older, smaller engine combinations, like a 301 small block combo. Mopars, with the shallower valve angle and round open chambers really don't need to be angle milled. In fact they need to be flat milled, if we are dealing with typical OEM open chamber heads, and trying to take them to the max. By the time it is flat milled to a closed chamber, you are already pushing it, so angle milling on these heads is a complete non-starter.
If you read all that and decide that you want to angle mill anyway, now your manifold angle is off and needs correction, and pushrod holes are off and may need correction too. Your head bolts holes will also meet the block at an angle and you can get busy correcting the spot-face on the bolt holes and clearance the holes top and bottom for the angle. Hope this gives you all the info you need on angle milling.
-dulcich
mike