My take on the oiling system crossover tube for the small block

So I put the 90* adapter on yesterday and hooked up the pressure gauge in the photo shown. (looks close to the header, it is not)

View attachment 1715243371

That goes to the AutoMeter gauge in the Middle , and the AutoGauge on the left is back of the engine. I had my idle real low trying to get the lowest idle speed to capture the lowest pressure reading. (I had to blip the throttle to keep it from dying) For some odd reason, oil psi isn't going as low in idle like in the previous videos. Take note that the AutoGauge on the left reads consistently a little lower pressure on all my videos.
Colder oil temps perhaps? It would be instructive to swap the gauges and see if the lower pressure flows the gauge on the left. Sounds like it would from your last note.