I have a '76 Mk3 with a 998, HS4, dish pistons and an unskimmed 12G295 head, and has likely been running this setup since the 80s or 90s. It does 135 psi across all cylinders and a 7.8ish compression ratio.
I'm debating what to do to improve power (it has trouble climbing hills) that doesn't involve removing the engine just yet. I put in a Powerspark ignition which has helped, and a stage one was also on the agenda early this year. One thought was to find an original head or have this one skimmed, if it can reliably be done with dishes. Or should I even be concerned about the low compression and keep on with the stage one? Thanks!