Based on my own experiences with 1951 and 1952 Kaisers that used the same temp and pressure systems, here are a few thoughts:
1. The water temperature sender in the block deteriorates over time, and as it starts to go, it does not read as high as reality. A simple but not entirely accurate comparison is to run the engine for a bit to get it warmed up and VERY VERY CAREFULLY, SLOWLY remove the radiator cap. Insert a kitchen thermometer to check the water temperature at the top of the radiator (the hot water return from the block). Start the engine and compare thermometer with dash reading, remembering that the mid point on the gage should be 170 or so degrees F, and the H end should be in the range of 212-220 F. If the sender has deteriorated, it will read about half way between C and the start of normal range at around 160 F and will be close to 200 F at the halfway point. When replacing the sender, make sure you do NOT put in a sender with the mark "240" on it. In 1953, the sender was changed and the dash gage recalibrated for a top end of 240 F. The temp range change in 1953 is per the shop manual.
2. Because the electrical system is positive ground, as the oil pressure sender deterorates it will show LOWER pressure than actual in the engine; Fords, in contrast (with positive ground) will run higher, going full deflection when the sender fails completly. I have had a sender fail completly with no pressure (that was scary first time around). Long-term ownership and operation of the Business Coupe suggests that senders have around a 15 year life cycle.
3. 1951 Kaisers have a mini voltage regulator that again, wears out with time. The best detector on this is to run the car, turn on the headlights, drive and watch the temp gage (assuming that the sender is working the way it should). Use of the lights will affect the electrical balance of the system and you will see the temp gage quickly shoot up to full deflection (at or right by the H side, regardless of outside air temp). Turn off the headlights and the gage should drop to "normal" in a short period of time. If this happens, replace the regulator, the small metal thing with wire connectors on the back side of the instrument cluster: Nash automobiles of the period have a similar set up and can be checked in a similar manner.
Jack Mueller