Ive seen over the years on this forum over and over the same problem;20 years ago i had the same issues couldnt ajust the oil preasure correctly on my race hemi, millidon twin pick up adjustable relief valve trw pump.came to the conclusion the relief system cannot flow enought oil to maintain the preasure the spring is set at: I now port out the casting around the piston widows with a small round burr in a die grinder and smooth and massage the piston window with a small stone in the grinder, use the correct grade of oil, in my case 20 w 50 i use a accusump never had any problems since.
