oil pressure question

what do you guys have for oil pressure? i have a mopar high volume pump. 340. only started motor a few times. seemed as oil pressure was around 70 psi the first few times i started it. now this last time i let it run for a pretty long time and got the header tubes red hot, but my oil pressure dropped to 50 at idle, then 40.....then down to 30. put it in gear it might drop a little lower than 30....but if you give it gas it shoots back up to around 70. i know about all the areas to check. but are these numbers matching anyone elses? thanks