True.
But there is enough meat on that head to shave off quite a bit without having to worry about it.

You can also get a new set of pistons clearanced for valves by a machinist. They just cut the scallops in it. They should be able to handle that.

You should always check for piston to valve clearance though. It's very easy to do. If you deck the block or shave the head, it could be critical. Especially if you put in a cam that has more duration.