If it's warm at the track my car will occasionally loose all oil pressure, like 1-2 times a weekend at the worst, sometimes not at all. I shut it down and drift in if I'm close enough to the pits or I pull over and wait to get towed in.
After the engine has cooled a little bit, sometimes as little as 5 minutes, I can start the car again and all is well.I suspect that the oil pressure relief valve is sticking, what do you guys think? How could I fix this short of a dry sump system? I'm building a 2.7 to put in it right now so I can't spend a fortune on the 4.

Had a similar problem with the my car and it turned out to be a bad electrical connection.

I have a separate gauge and light, they agree that the pressure is gone when the light actuates.

Usually the seperate guage and seperate light are still powered by the same (dual) sender

replace the sender

I'd definitely look at wiring first
its the cheapest to repair