This has been bugging me for 2 years already. BOTH my motors experience this. One is a 355 and one is a 383. Both were built by Victory Engines, Inc. in Cleveland. I'm running M55 pumps with #26 springs and also stock replacement Miloden pans. Driving around is perfect, highway perfect, 55 on the highway and 30ish at idle HOT. Whenever you nail it it pegs to 60 then falls quick as the rpms rise. As soon as it shifts or the rpms climb slower in another gear the pressure starts to go back up. Pressure never falls under 30 psi I have not use a mechanical guage, but could it be so much pressure its bypassing the elec guage above the filter? I pulled the bearings and all is perfect after 3000 miles with about 20 laps and a few dyno pulls. When the oil is colder it'll drop to 45 instead. I dont have the specs on the clearances off the top of my head but both main and rods fall in between the guidelines in the Lingenfelter book. Any clues? Oil PSI sensors are new too. did it with old ones and new ones. It has done this even with the old stock motor and new pump. I've changed the OP springs, same issues. Do I not have my sending unit in far enough at high RPM or something?

One motor is a 383 L98 Block TF Heads LPE219 cam and Miniram Other motor is a 355 LPE216 cam and Stock TPI intake.