The engine in question is an LA 318 in a '72 Challenger.
Everything I have found indicates that the oil pressure sending unit should be on the back of the block close to the distributor (like a SBC, remember I USED to be a Chevy guy ), but I can't find anything. There is a threaded opening on the oil filter adapter, but I hope that isn't it as it appears open (nothing it it) and no oil is leaking. There also feels like a plug or something on the other side of the filter housing. I'm 6'6", 340lbs so I haven't crawled under to investigate further What am I missing?

And... thanks to all the members who responded to my first post with an electrical question. Your advice got me up and running!

Randy

Should be right next to the distributor on the right side. If you have a light then it will be a flat goofy hexed shape with a wire going to the top terminal. If you have a guage it will be a bell shaped sender with the wire also going to the top terminal.

Should be just to the left,behind and below the distributer on top of the block.

There should be a threaded hole at the rear of
tbe engine block near the distributor, that is
where the oil sending switch screws into the
engine block.....same basic place as it does
on a big block too.

So it's on the top of the block(pointing up like the distributor) and not on the back of the block? I remember seeing a small allen head screw threaded into the block in that approximate location. It looked pretty small, but that has to be it?
Don't know about a light as the dash was not installed when I got the car and the engine is a rebuild that was dropped in before I got the car too. There definitely isn't any type of sending unit in that vicinity.

Yes it does point up. That allen screw is probably a plug in the oil pressure hole.
MoparforLife , That was to the left of the dizzy not the left side of the motor.

Thanks guys! I am pretty sure I know where it is now.