Water PSI too HIGH what to do???
 

I have a 35 Lighting, it's a 93 flat bottom boat with Xr's and 2" Shortie Imco's with pickup in the nose of the drive. We have Merc Bypass valves that relieved at 25 however when approaching 80+mph the water PSI still went to 35 on the dash. I did some research on the merc bypass valves and a few guy recommended a new weaker spring for the bypass so I bought them and installed them. With the new spring installed they relieved at 18PSI but still were over 30PSI at 80+MPH. The boat does not have strainers but I am going to install some and thought I would add a set of hardin bypass valves on the strainers in the port where the chiller line would run, while leaving the merc ones inline still where they have been before the cooler on the starboard and after the cooler on the port (just for neat plumbing). Any ideas or input would be great. I do have Stelling boxes on the boat also with the drive in the highest position. The "X" is now 3.5" over the stock "X". Thank You in advance for any ideas or input.

How/where are you dumping the water, and with what size fitting?

At the current time the MERC bypass exit through a "side thru-hull" like the bilge pump fitting, they have their own on each side for each side. If I do the ones on the strainers I'll prob put one on each side in the rear under the exhaust or next to the exhaust.