Im thinking that its wearing in, and unless you did the engine yourself and are exactly sure of bearing clearances, maybe a little too much.  I know with my Flathead Ive just rebuilt  when I started hot idle was a good 30+ now after a few hundred miles its down and settled at 20. 
keep an eye on it . 



"Came too close to dying to stop living now!"

D Bird: In your case, if your light is coming on at hot idle, your pressure is at  5 lb or less!  There's something seriously wrong there. I wouldn't be driving long distances in Hot weather like that..


Paul

Paul, thanks for your concern, which i share.  After going to a heavier weight oil, I haven't had an issue with the light, though the gauge barely reads 10 at a hot idle in drive, so if it's going to idle any length of time, even a red light, it's in neutral.  I will note that the first time for the light was over six years ago and the engine's still going strong.  Of less importance, it's not the original engine so it's not like I might be ruining the originality of the car.
Don

I'm going to change out the oil pump in hopes that that fixes the problem. How tight does the tube nut have to be?

Durham Missouri

I'm no authority on this and have no specs, but I just replaced the pump drive rod in mine. I put the rubber sleeve on the pick up tube for the install. I could feel the resistance of the rubber as I tightened the nut. Finally, it felt like the nut ran out of threads and I didn't push it any more. I know the nut wasn't very tight when i removed it. It just takes enough to push against the pump body and squeeze the rubber around the tube. 

my 292 has a few miles hot idea is15psi at 650 hot. i would look at oil to rockers if you have groved cam and cam bearing the rockers will bleed of oil pressure ,especially with return tubes. in my case i block the tubes off completely. with the cam that has holes the oil is metered,i would still block off the drain tubes. if rockers and shafts  are good you will find better oil pressure at idel.  if engine is fresh  like previous poster noted check the relief have, possible debree holding  valve of seat, or sticky valve due to debree.

From the Torque limits section of my trucks  shop manual, 10-12 ftlbs, real easy to overdo.

Invest in a shop manual.


Lawrenceville, GA

Hard to put a torque wrench on that nut, but from my feel you would have to bottom out the nut to get that much. 

If you bottomed out that nut, then you have overtightened it.  There are torque adapters and crows foot wrenches if you want to get a wrench on it.

I just snug it, start the engine to make sure there are no anomalies.  If pressure is good, I make sure oil doesn't drip out of that nut after being shutdown a while.  If it does, I tighten it a little more.
If pressure drops, then the nut is possibly too loose and air is being pulled in.  Tighten until pressure is normal or it seems to be getting tighter than should be required without fixing the problem.


Lawrenceville, GA

Just a thought here-

If this discussion is BIRD, then maybe the pressure is dropping because of engine heat (small engine compartment - overheat due to BIRD WP positioning).

If you do decide to replace the pump, consider a MELLINGS HV with an ARP shaft.

____________________________