I have an '84 truck with a 305 that someone took from a car (about '86, 1-piece rear main seal). When I got it, the temp and pressure gauges were unresponsive. Just installed a new temp sensor and oil pressure sensor.
When I first start it, the oil pressure is off the gauge (over 60) until it warms up. After warming, it reads about 50 while idling. The temp gauge reads 210 as soon as I crank it, which of course is wrong. Then it shows almost in the red (260 degrees) while idling. I shot a heat gun on different places in the engine while idling warm on a 70 degree day. Everything reads about 150. Radiator and hoses, top and bottom, both read around 180.
When I rev the engine, the oil pressure goes up slightly and the temp goes down slightly almost in perfect sync with the gas pedal. Is this normal?
Is it possible these gauges are not compatible with these sensors?