In the early days of ss racing a 71 cuda on the decel end of the track the pressure would drop and the engine would labor to crank. Really didn't know what was going on. After a catastrofhic explosion we found the oil pan had the baffles removed so the oil would go to the rear at accel and suffer the pickup of oil. hard lesson. Not sure what pan you have but it will move the oil from the pickup to the rear at accelerate if not baffled correctly.