3.3 bar, obviously at this boost level the head is lifting causing the gasket to move/blow. Any gasket will blow if the head isnt secured. Is it blowing in the same spots? Does it blow if you turn the boost down?
My guess is the dodgy adjustable pressure reg has a tear in the diaphram causing fuel pressure to go up the vacuum hose into the manifold-instant flooding
I recently had one repaired by a company called industrial hardchroming in Sydney, They weld it, then chrome it and grind, recut the keyway, only cost about $200