OK

the original gauge was 0-30 ohms
A "12 volt" replacement sender might be rated 0-90 ohms.

There are replacement gauges that use the original rating, and, there are replacement gauges are made to work with the newer/higher rating.

Mis-matched sender/gauge could give the readings you describe.

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.