HPDE Time Attack enthusiast chiming in here with what I have seen with tracked FA20s.
I have just blown my 2nd head gasket. Both gasket blew under boost. 8 psi and 12-13 psi respectively. Both engines had about 40-50 track days on them.
Two other track buddies blew the gaskets under boost at about the same # of track days.
One track buddy blew his gasket while NA (header + tune + e85) but his motor had 60+ track days on it.
All of these drivers were driving at a rate of ~20 track days per year.
First symptoms observed by all drivers was coolant overflow bottle was overflowing with coolant during hot laps. Combustion pressure pushing coolant out of the system. Black specs of gasket coating could be observed in coolant. At idle with radiator cap open bubbles could be seen periodically rising to the radiator cap neck.
