That is as it should be. Ours has also been stable with the stock pan and I went back to pull some data from the oil pressure sensor that we log into the Traqmate. It is rock steady except for shifts where it drops down a bit, sometimes 10 psi if the shift is slow, but it typically hovers around 52psi when good and hot from 1200 RPM to 5100 RPM. Here is a plot, the third trace is oil pressure vs distance for one lap of RRR, our last race we entered.
http://www.gt40s.com/images/Mustang/oilpressure.jpg
The oil pressure drops during the shifts, the gear position is shown in the fourth trace. There is a little bit of a drop around 2300 ft that is due to g loading I suspect but I'm not too worried about it, at least not yet.