340 High Compression Pistons
You can use the pistons in post 7 if you are using open chamber heads. If they are not open chamber, you have to mill the quench pad.
Funny thing is, that's the piston I'm using. If you are wanting max compression you'll need a positive deck height of .060 or a bit more, depending on gasket thickness and chamber volume.
Finding a machinist who will do that may be a PITA. But that's the correct way to do it. Don't mill the heads to nothing. Shorten the decks.