91 blazer engine

i bought a rebuilt 4.3 engine for my 91 blazer, installed it and added all the covers and parts from my old engine, primed the lifters thru the distributor hole then installed distributor and cranked it but only ran it for a minute as it was running very rough and smoking bad, pulled off valve cover and didnt seem to be getting much oil in the top of engine was basically dry , am wondering if the valves are staying shut maybe or could it be something else? all suggestions welcomed, thank you,
mwj

How did the top of the heads look with the valve covers off? Any sign of sludge build-up?

I'm just saying this because maybe the oil gally holes are plugged. Or maybe the oil pump is junk?

Remove spark plugs.
Remove fuel pump fuse.
Disconnect primary coil wire.
crank engine over with starter and watch for oil through push rods.

headss looked good everything wsa clean, but should be was a remanufactured engine, new rods,lifters,pistons,etc. and a new oil pump and screen, still stumped as to why oil hsant came to the top,someone told me that i may have to get the motor to operating temperature before lifters completely fill with oil, whats the thought on this?

I dont know much at all about the topic, or why its doing that, But i don't think it would be smart to let the motor getting to opperating temp before you have oil up there. Due to the idea, may be by the time oil got there, it may be too late