my uncle put together a 13 to 1 468 for 1 of our buddies and when your in the water idling it has 60psi and as you step into the throttle, the pressure steadily goes to shit, let off the throttle, pressure builds right back up to 60psi. it has a 10qt trap pan that's in great shape, new oil pump and the pick up is about 1/4in off the floor of the pan, runnin a full 10qts of oil in it. this same block ate a rotating assembly up prior to my uncle's overhaul job and now it has us both wonder if the block is flexing and opening up a crack in the galleries. someone converted the block into a splayed 4 bolt, started out its life as a high nickle 2 bolt. any chance some cracked the block when they did the 4 bolt conversion? i've never seen such a thing, has me puzzled. makes sense that the last crank got smoked at wot, cause as long as you're holding the go pedal down, the oil pressure continues to dive we didn't hurt anything testing it saturday, noticed the issue right away and put it back on the trailer. clearences were as perfect as perfect gets, has new cam bearings, its non restricted at the cam gallery, fully roller motor.
what would make the oil pressure dive where it'd normally climb with throttle? there's no bearings bad, its already back on the stand, just not see'n anything wrong anywhere other than the block has been tampered with at 1 time.oil pressure bypass in the filter adapter is blocked as well.mark 4 block