Remote oil ports. Which is send and which is return??

Pickup tube is tied to a main bolt and bolted to bottom of pump. I f you can get pan off in car, then, ok.
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So, did it lose oil pressure at the track? Or did you park it for extended period of time, and, then nothing? Sorry for the questions, pieces to the puzzle.
It lost oil pressure at the track. It sat for 20 minutes between rounds cooling off. So, not an extended period of time. It made 4 passes with good oil pressure.