The oil pressure circuit in the SN95 was never meant to be accurate, anyways. It's more of a 6psi switch rather than a sweeping gauge. Ford determined if you has at least that amount of pressure, things were ok inside the engine.
There is a way to make the oil pressure gauge accurate and sweep across a range. Mark Olson at accutach.com figured this out and made it public. I've purchased all the materials to make it happen in my car, but haven't done the work yet (and it's not bad).
His procedure replaces the OEM 6psi switch and uses a true pressure sender (rather than a switch).
The OEM oil pressure "gauge" isn't really a gauge, it's an "idiot light" cleverly disguised as a gauge.
I wasn't aware of the accutach.com kits, but I did the same basic conversion on my '97 GT using a MeterMatch (technoversions.com) and it works great. It was a bit involved, but very much worth it to see what the actual oil pressure is, not that it's "over 6PSI".
I was also able to hook up the unused "oil" light in the '97 gauge to the warning light feature on the MeterMatch so that it flashes if I have low oil pressure, which is great if something goes sideways - I have a chance to shut down to try and save what's left of the motor. IIRC, that light was used for the low oil level sensor on the first year or two of the older 302-based 5.0L SN95's. It was present in the cluster and unused on my '97 with a 4.6L, so I used a scavenged terminal from a parts cluster connector + (IIRC) a new bulb to hook it up, and it works very well and looks factory. I kinda wish there was an easy way to make the earning light not blink, but that's how the MeterMatch works, so I just used it.