Greg Beckham

I have a 1996 Vortec 454 reading low oil pressure at idle after warm-up, 131K miles, well maintained. After warm-up it will read between 4-8 pounds at idle and makes the check gauge like flicker. Yesterday I swapped out the sending unit; no improvement. Question: Is there a place by the oil filter or other that I can tap with a mechanical gauge to confirm the situation? I am aware there were changes to the block in 1996, L-29/Gen. VI I've researched and found some have gauge issues, others; sending unit; yet others having exactly the same symptom as me- it's actually the clearance in the bearings. I'm actually leaning towards it being bearing clearance issues and if so that sucks considering it being in a light duty truck, lots of BBC's used in heavy-duty applications with good longevity. I want to Thank-you in advance.