Video Link below. What would cause my oil pressure to fluctuate like this? Constant cruising speed it will drop almost in a timed pattern. 400 Pontiac block stroked to 460, Solid roller cam. Wix Oil filter and I know the Filter bypass in housing is plugged. VR1 20w50 oil. I have already tried another mechanical gauge. Same result. Pressure taken from oil filter housing. 4an braided line. I have only had the car for 2 years and have put a good amount of street miles on it. Oil pressure rises with rpms quickly. Cold oil pressure at idle is 60psi +. When fully heat soaked I am getting 20psi in neutral and around 10 in gear. I am looking for input before I pull the motor out. Thanks.