just pull the motor out of it and work on it on a stand, if you search you will find directions everywhere

 

Motor is easiest to take out of the bottom.

 

This is the only way to fly.

 

What about a bad lifter?I try and check them out.

 

Ok if your looking to get to the bottom end without removing the engine, its a dirty job but can be done. Extensions and swivels are yours friends on this one. My buddy and I replaced a worn rod bearing in his lt1( yeah different engine but same theory) 1) Jack the car up. 2) remove exhaust if stock setup and drive shaft, leave it in neutral. 3) drain fluids etc 4) use the swivel and extensions to reach up in there and you should be able to take all the oil pan screws out. 4) remove the oil shield and **** thats in the way of the assembly. 5) with a sound like that, the gap or wear is probably bad so you might be able to simply take your fingers and wiggle the connecting rod or base of it that goes on the crank. 6) if you find it, remove the bolts and rotate the assembly so you can get to both sides of the bearing 7) measure out the depth by using the gap tool? (can't think of the name off my head), replace as needed and reassemble... thats the way we did it....

 

No way thats a bad lifter, not that damn loud....thats def. a spun bearing
Feeler gauge my friend

 

Chances are very good that the crank will need to be replaced so even after all the work to get the pan off with the motor in the car then you'll have to pull the trans too.
It's just soooooooooooo much easier to just pull the motor/trans out the bottom.

 

if u replaced ur oil pump, u might want to check the seal for the oil pump. i heard a car make that same noise turned out to be oil pump pickup tube seal

 

Thats one of the issues that GM said might be causing "piston slap" on some LS1 engines. Have you ever heard piston slap? It sounds nothing like GhostZ28 knock issue.