Truck has been sitting for 6 most. Replaced fuel pump. Fired right up. Lots of clattering. Yanked valve cover and no oil movement. Today gonna yank oil pan and front cover. Assuming cross member needs to be removed. Read posts about oil pump common failures and timing. Might have to replace water pump and or timing chain stuff since we're in there already.
Any helpful hints? Thanks.

The cross member Doesn’t have to be removed. Before doing anything - Remove the fuel pump relay - Remove spark plugs so the engine turns over freely - Spin the engine over good possibility you MAY get oil pressure. Also on the top of each rocker there is a plunger that may be froze up causing the lifters to clang and a lack of oil. Pretty common feature. This site offers a FREE factory service manual which goes into detail on repair procedures. Could also hook up master positive pressure gauge briefly run the engine to see what the actual oil pressure is. Right below the oil filter is the oil pressure sensor. Remove the sensor and screw the master oil gauge in the hole.

Another extremely helpful hit. Before running the engine I would highly recommend placing the rocker arm cover and the oil cap on. Reason being before you can shut the engine off you and everything around you will be coated with oil.

Yet another possibility there’s a oil pressure relief valve on the oil pump located towards the back of the pump. Possibly the valve isn’t functioning properly.

Even when you get oil to the rockers it could take awhile before the rockers quit clanging. You can try keeping the rpms at roughly at 1k up to roughly 10- 15 minutes.

Dropped pan. Removed oil pump. Pick up looked ok. Pump had some gooey oil in it. Passages to and from pump were dry. Figured I would blow some air thru the pickup tube passage and inspect filter next. We probably ran engine for 10 min total but not all at once.
Removed plugs and pulled crank thru multiple times. One cylinder is much harder to pull thru. Don't know whick one yet but seems to be less than 180 degrees rotation. Figured to lube cylinders thru spark plug holes to cure or identify problem.
Vehicle owner is busy cleaning all gasket surfaces. That's kind of a plus. Takes a while to do it right. He spent better part of a day on the tank. It was nice.

Sounds like a good plan. I just can’t see tearing down the engine replacing the oil pump only to find out that wasn’t the problem. Personally I would only remove the oil pump and the timing cover as a last resort. Usually if the chain is bad it will rattle when the engine is started. Look for pieces of the chain guide in the pan.