I just bought an 88 f250 with a 460 in it. Test drive went well, needs some work but it seemed fine. Driving it later I realized that the oil gauge moves around a lot considering it's supposed to be an on/off switch. It will dip and show no oil pressure although there is no valve chatter or noise, so I'm certain that it still has pressure. When looking up the oil sender location to inspect wiring, I saw two separate locations, center on the rear of the engine by the intake manifold and by the oil filter, which is it?

 

On the 460 it's in the back of the engine, behind the throttle body.. The small block V8's have it down by the filter...