i do not recommend mechanical gauges. go electric.
the oil pressure sender is next to the oil filter on the side of the motor. your sender would go there
for water temp, there are two water temp sensors on the motor. they are located on the portion of the intake manifold where the upper radiator hose connects. one has two wires. leave it. the other sensor is a single wire sensor. this operates your gauge cluster temp gauge. remove it and install your new sender there. rethreading may be necessary
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RIP Tim. i miss you, buddy