Oil Pressure / Oil Leak

There would have to be a pretty massive oil leak and pressure drop to cause the sender to respond with a light.

Michael, my guess is that:

1. As you stated, you most likely have a leaking upright oil cooler, don't ask me how I know. How is the oil level?

2. Your oil light may be coming on because oil in the line to/from the filter adapter could be  cavitating, why, I don't know, but the sender is usually installed in the block, driver's side below the fuel pump where it constantly receives oil (usually under considerable pressure). You didn't say whether or not you have a remote cooler?

I drove it several miles home after the light came on. I felt somewhat comfortable doing this because the gauge still indicated pressure.

When I got home my oil level was still good.

The pressure light sender is located in the usual place near the distributor and fuel pump place.

Having this happen at the end of the week caused me to miss the Woodward Dream Cruise with 40,000 cars and a million people.

Mike wrote: "When replacing the sender with a new one I noticed what looked like oil leaking out where the fresh air outlet connects to the main shroud. "

Sorry, EOA moment and I cannot visualize that place.  Can you provide a photo?

It is totally common for the oil pressure sender to leak, usually out across the case from the distributor left-ward and up/down on the case around the sender.  When that happens, the sender often loses pressure (but not the system) and the light (normally closed) is allowed to come on.  It can look like the oil cooler is leaking, just from the amount of oil spewing out of the pressure sender because it shoots out under pressure and can go anywhere and everywhere, depending on the nature of the leak.

Now that you have a new sender in there and want to clean things up, anyway......Blast the hell out of it with a good degreaser and hose it off, then let it dry and drive it a bit to see if you see any more oil sneaking out.  That's a good first step, versus pulling the engine out to pull the fan shroud to find nothing (or something).  

Also, an oil cooler leak will show up in the center, between #3 and 4 barrels and down the case, on the underside of the engine (and the fan blows the oil straight down).  A leaking pressure sensor will show oil at the rear of the #4 barrel where it meets the case.

Oil didn't seem to be leaking from the pressure sender.

On the fan shroud, there are two outlets that hoses connect to that then go to the heater boxes. Oil was coming out where these two protrusions attach to the main shroud. Since the oil has some air pressure pushing it, there were also oil deposits on the underside of the engine compartment lid. The oil being pushed out was black and thick, even though the oil on the dipstick was light colored and thinner. Maybe it was congealing for a while before being pushed out.

I do have a little more air pressure inside the shroud now because I replaced my 6.75" crank pulley with a 7" one.