440 Oil Pressure

[Challenger340]

If you think increasing the relief valve spring tension will increase your hot oil pressure, try it and report back.

Hundreds before have done just that and wasted their time.

If the need arises I will.
Done it before, and I will do it again when required, and Thanks.

Dunno what the "hundreds" did to fail ?... or how they reported back to you that they did ?
But here's what I do.
Read it in a service manual when I apprenticed at a Chrysler dealership back in the 70's.
For used Pumps....
* Remove Pump and dis-assemble.
* Check Rotor/Body "stack height", Polish as neccessary(down to .010")
* Polish grooves out of top plate/filter housing
* Re-install Pump
* Shim relief spring externally as required, until desired pressure reached.

Done it on the Dyno a few times of late as well.... but those were NEW Pumps, so no Stack Height dimension work required... just shim and go.

[ChargerKen]

In any hydraulic system the relief valve is installed so that the pressure in the system can be regulated to a predetermined setpoint. That's why shimming the spring raises the pressure. If you were to shim the spring and the pressure does not increase then you have reached the maximum flow of the pump. Pressure is resistance to flow. Bigger clearances in bearings; equals less resistance to flow; equals less pressure;  if the pump won't flow enough oil to unseat the relief. If the pump will flow enough oil to unseat the relief then shimming the spring will definitely raise the oil pressure.