I'd be curious if the new oil filter is full of oil. The filter sits vertically, so it will stay full of oil.
Do you fill the filter full of oil before starting, or just lube the seal then install dry? Either way works, I prefer to fill the filter if possible before installation (only possible on engines with filter facing vertically).
The statement above is completly accurate, no need to prime an oil pump, they do it rather quickly.
It's possible that your gauge has died. Where do you get your oil pressure reading from? Mechanical gauges usually have a plastic pressure line, it's possible for this to become kinked or pinched for example, so examine the line and the gauge when swapping reading devices.
Do you have an electric oil pressure gauge as per the factory?
lastly, before you give up. Might try overfilling the crankcase with one extra quart, so that you have 8 quarts of oil in the crankcase. Know someone on here that ended up having a cracked oil pump pickup tube, overfilling the crankcase with oil revealed the crack, because he got oil pressure when the oil covered the crack...
Keep us posted.
As per your technique. No need to drain overnight, if anything it's a source for dirt (engines worst enemy) to enter the oil system with an open oil filter housing and or missing drain plug.
1982 C10 SCSWB 6.5TD, mods too extensive to list. (13.69 1/4 mile @94.6 MPH) RACE TRUCK
1982 C10 SCSWB 6.2NA, 2.73 700
1986 C10 SCLWB 6.2TD 3.73 700
1989 V20 SUB 6.2NA, 3.73 400
1994 G20 VAN 6.5NA, 3.42 60E
1994 K20LD ECSWB 6.5TD, 3.42 80E
1995 K20 SUB 6.5TD, Wrecked, ran into by stupid teen.
1995 C3500HD DRW 6.5TD, 12' Flatbed 5.13 80E
1995 C3500HD DRW 6.5TD, 18' Rollback Wrecker 4.63 80E
1994 C20HD ECLWB 6.5TD 3.73 80E Wifes Truck.
1995 C20LD ECSWB 6.5TD 3.73 80E
1995 K20LD SCLWB 6.5TD 3.73 80E
1996 K30 DRW 6.5TD 4.10 80E
1997 C10 Tahoe 2Door 2WD 5.7L to 6.5 Conversion Underway