420A Turbo oil return question

[Carter_95RS]

okay, so earlier i was out working on my intercooler piping and getting all of that taken care of when my dad mention's something about having to remove the oil pan to put all the stuff on it to get the return line in. honestly, i'm tired of hearing about it and then he mentions this

"why cant i just drill and tap the valve cover and put the return line there?"

i honestly dont know how to answer this, my guess is that it would have been to much oil in the valve cover and it wouldnt drain right.
what are your thoughts?

 

[VelocitàPaola]

Oil drains out of the turbocharger by gravity. It would just collect in the turbocharger and damage the bearings if the return was connected to the valve cover.

 

[Bender]

It needs to go to the oil pan, above where the normal oil level rests.

 

[Locke]

Above normal oil level, and below the turbo oil outlet.

If the turbo were mounted above the engine, then you would be able to have it drain into the valve cover.