Oil pressure logging on a blow 402 V7

[hotparts]

guys i always looked at the oil pressure a little bit during tuning the car with the HP Tuner and it seemed that it rises from 320 kpa to over 450 under full load at 100% TPS with a 10W40 oil. Now i made a log at the HP Tuner and saw that it goes down till 250 kpa under full load. Is this normal or do i maybe have a restriction with an K&N HP-1007 oilfilter on an LS 2 with LS1 oilpan? The Motor is a 402 with V 7 and over 1000 HP.
Thank you

[Montecarlodrag]

So, the same engine went from 450 KPa to 250 KPa at WOT? If we are talking about the same engine then you have a problem
250 KPa equals to 36 PSI, too low pressure for WOT

I would go back to the oil/filter you used before and test again