hi all, i have been restoring my grandfathers 66 mustang 289. i did an oil change a few months ago and have noticed high oil pressure and a slight leak at the front and back of the block. when driving, the gauge will hover around the middle and teeter between there and the line before H. I replaced the filter twice, replaced the screw and gasket and then the oil pressure sending unit and still see the issue. neither the drip or the gauge were abnormal before replacing with high mileage pennzoil 10W-30 (non synthetic). anyone have any ideas? should i be worried? thanks!