Quote:

Since you are unsure if you will be reducing the flow
I would drill and tap the point just below where
the rocker shaft mounts, that would be the easiest
point to change the restriction (not having to pull
the heads to change it if it was in the block surface)


I agree with Mr.P on the where to put it. But I don't believe restricting the oil to the top end is a good idea for 99% of us. Heat is a big killer to valve springs and I would rather have all the oil I can get up there to keep them cool.
I would rather work on better ways to keep oil returning fast and off of the rotating assembly upon return than restict the oiling.
Keith

www.dunnuckracing.com