sbc oil pressure drop ?

[jasonsnova]

my 355 in my nova after a high rpm run when i let off it looses oil pressure, it goes down to probally 15-20lbs from 70lbs, and if i bump the throttle it comes right back instantly to idle pressure of 40-50(hot) , now ....it never did this before until i switch pans, i went from a moroso 7qt deep sump(it was fine) to a 7 qt side kick out style (off brand,i think it was a summit one) it did have the matching pickup with it too , anyway im pulling the motor shortly for a trans swap and am going to change the pan ...again, any suggestions on pans? 6 qt ? 7 qt? should i just go back to the deep 7 qt style(which i didnt have a problem with!) anyone have a simular problem? the car does have a early 70 lt1 style windage tray too.