Chevrolet Repair: 1974 cadillac oil problem, cadillac 472, pressure gauge

Question
Hi there,
    I have used this forum before with great success.  You guys are great.  Now here is my dilema.  1974 cadillac 472 engine.  100% stock.  Using it in a (bomber class) track racing.  Problem that I am having is that coming out of a turn, I lose oil pressure, and get lifter tick.  I also lose power.  I have checked the pick-up tube and screen, and they are sitting aproximately 1 inch off of the bottom of the oil pan.  It also loses oil pressure if I substain higher rpm .  The oil return passages seem to be clear, as the inside of the engine is super clean.  Please help me out, as I am lost to the cause.

Answer
What kind of rpm's are you pushing when you notice the pressure loss?
Are you using a pressure gauge? If yes, what are your readings?
What is the temperature of the oil during the race?
When was the last rebuild on the motor?
Sorry for all the questions.