New SO lost some oil pressure 40psi

[jimmymac]

Really glad I found this sight ! Im about ready to pull it out and go through it! About the third time out. I bounced it off the rev limiter,7000rpm. no problem i thought next time i looked at my oil presure it was only 40psi @2500 not the same as before. It will get 40 around 1500rpm If i rev it the gauge will bounce to 44 for half a second or so then back to 40 no matter what rpm! I pulled the oil pan tested the pump 85psi. put it back. Put some oil to it spun it ele. drill cold oil 55psi 1500rpm=3000motor right? but it never did have a lot of resistance. Pulled #4 main looks new mic.ok .003 clearance. Pulled a rod cap still looks good! Pulled intake,thought maybe a lifter galley plug had been left out or something. OH rods have .003 also. well no gushing oil anywhere escept a good even stream from all the rods and mains. I had no idea how much oil that speedpro pump moves. Castrol 10w40 oil two ph8a filters and oil cooler if it were plumed wrong it wouldnt flow right. Im sure its correct. I pulled the remote adp. on the block hoping to find a blown gasket ,wrong.It was ok. oil relief valve moved ok. How much tension does this spring supposed to have? I can move it with sm. screwdriver easily. Im not sure its 36years old! Could it have stuck open when hot then closed later? Ive been told Rotella oil sound like a good idea? Any experience with this Problem!!!! Any thoughts what could be happening here. This system worked very well in my 63 block. Should I keep the relif valve in the rear? Any help or ideas would be greatly apprecated. jimmymac