Oil drainback: Do all the small and big blocks drain the oil back through the lifter valley?

[Kern Dog]

This is a topic that I never thought of. Oil drainback. Look at the picture of the deck of an LA series:

Here is a 440 block.

All I can see in both blocks are coolant holes and head bolt holes. Does all the oil that makes it to the rocker gear drain back through the lifter valley?

 

[1WildRT]

Yes... But now look at the heads near the front & rear...

 

[Kern Dog]

This picture may come through small....

With the #308 heads I have out back, I couldn't see any drainback holes, just the open spaces above the chambers.
Trick Flow:

 

[1WildRT]

Those openings are the drains, the majority of the top area slopes toward the drains... A small amount of oil gets trapped but not much.... It would be nice if drain back was routed around the crankcase to the pan but these are production engines intended for passenger car duty, not special race pieces...

 

[413]

Yes they drain in the lifter valley.

426 hemi drains out the corners of the heads into the block and to the pan.