Made the test with oil gauge and had between 2.5 and 3 bar which is about 40psi with engine cold at idle.  At this point i guess that the engine is healthy and bulb is gone!
Bought a mechanical oil pressure gauge to keep everything under control in the future.
Thanks everybody for your help.

20-25 psi oil pressure at a hot idle would be normal on a fresh engine.

Lorena, Texas (South of Waco)

Thanks Ted,i'll check the tube out of the oil pan.
I got an oil pressure gauge from my mechanic,he told me to check the oil pressure before doing anything else.
What oil pressure should a fresh rebuilded engine have @ idle?

The missing bolts are only contributors to an oil leak and not related to the oil pressure directly unless you’ve run the engine out of oil.  For your loss in oil pressure and assuming you have adequate oil in the pan, check that the flange nut on the tube going into the oil pump is ‘snug’.  If it’s loose, air can be sucked in there which in turn keeps the pump from pumping oil.

Lorena, Texas (South of Waco)

It is possible. I'd get a real oil pressure gauge and install  it to find out what you actually have for oil pressure. Lets start there.

Frank/Rebop

Bristol, In ( by Elkhart) 

Both of the bolts on the back of the heads were missing!!!!! So i think this is where the oil came from.
But now i think i have a bigger problem the oil warning lamp is on and the oil pan is full.Could the missing bolts have caused damages on the cam bearings or main caps or what ever causes oil pressure loss?

Check the rocker covers and pan under the intake also. can leak there and draft from the fan and air thru the radiator will cause it run down the rear of the engine.



Frank/Rebop

Bristol, In ( by Elkhart) 

Thanks everybody for your help,i'll get a closer look on Sunday and check if all the bolts are tight or missing and have a closer look to the valve cover gasket.

The threaded holes in the cylinder heads behind the intake manifold do need short 3/8-16 bolts in them as these holes are open to the pushrod holes.  One of these is under the distributor cap and the other is directly behind the water temperature sending unit.  If these are left open, they do leak oil.  Be sure only short bolts are used in these two holes as too long a bolt will contact the pushrod and bend it.

Lorena, Texas (South of Waco)

If you look past the fill tube you'll see a brass plug. That could be a leaking spot.

Triple Sevens CC
Central California