Got me a strange problem today. Went for a little drive today. Engine ran ok whilst she was cold, oil pressure is leaning between low and middle of the gage. When the engine got hot she started to drop oil pressure and she stalled. Restarted her, ran for about 15 seconds than stalled again.

Anyone have an idea ? Could this be a cooling problem / oil pump problem ?

 

You really don't give much to go on...

Oil pressure will drop when the oil heats up because the oil thins out. As long as you have 10psi per 1,000rpm you're all set.
Does anyone know what pressure is indicated by the stock gauge? The middle of the gauge should be nominal pressure of a 289 I would think,, but offhand I don't know what that is.
How was the temp gauge? Was the car running hotter than normal?
After it stalled the second time did it run fine?

It could be cooling, tuning or fuel related. I doubt it's your oil pump.

 

Very low oil pressure could make your engine prone to stalling. The pressure would have to be so low as to allow the lifters to colapse...

The stock guages are not known for their accuracy. You might want to try substituting an mechanical guage temporarily so you know where your oil pressure actually stands.

 

It could be vapor locking ,might be your problem