Same here on my '73 Dart. With a mechanical gauge you can actually see the oil pressure go away under hard braking.

For its next engine I added a baffle going round the deep part of the pan to keep some oil there.
I don't have a hard braking oil-pressure drops anymore now.

Hope to get the car on a circuit in a few months to see how it controls the oil during higher speeds and cornering.
I have my doubts on the side where the gap is for the oil-tube. That might still leak enough oil 'up' to cause issues on a long corner perhaps.