Your water pressure at 3,000 is normal. However, with speed WP should pick up. I would speculate that your x dimension is high enough that when you start to accelerate the water inlet at the bullet is either coming out of the water or is receiving highly aerated water.
I had this happen in my Daytona when I switched to a 2 inch shorty lower. I added a 1" spacer due to water pressure and prop ventilation which fixed both problems. I now run about 15 psi at 3,000 and run about 27 psi at 6,000