Since i love to beat the dead horse.
That chamber is stupid, either get the shortblock right with a set of zerodeck pistons and adjust the head to make the desired compression and get good squish. As a nice bonus you can swap heads later on if you desire to do so on the same shortblock,it also means that if you blow up the shortblock and your heads survive you can slip a normal shortblock without stupid popup pistons under them and keep you squish.
The only acceptable reasons to run popup pistons is if you already have them or you are racing in a class that requires them. all other scenarios get a closed chamber head unless you already have a open chamber head.
Its not that they dont work,its that they are a stupid limitation for future changes .
