IMO, you don't need to mill anything except to make sure the heads are FLAT and TRUE. You have a 340 with two eyebrow pistons and positive deck height. You WILL HAVE plenty of compression AS IS. Use the stock FelPro blue gaskets and you'll never have trouble. Mill the heads JUST to clean them up and no more. This is a driver. You don't want too much cylinder pressure on a hot afternoon stuck in traffic with your family. You want a driver. Something that's not finikey. Something that won't detonate no matter WHAT. You're not building a hot street or race engine, just a driver. Don't lose focus on that.
