I need oil restricting pushrods for my 403. I have some new ones from crane that I was planning on using. Im wondering what inside hole diameter of the pushrod is needed to restrict the oil to the top end?

 

I don't believe you would ever need restricted pushrods. The engineers want the oil up there for a reason.
Enlarging the drainbacks in the heads and block would be a better step to take.
Ideally, a sludgy engine never happens. In real world practice, it is not the case.

Oldsmobiles oil just fine from my experiences. When people have problems with too much oil up top, it's because their drainbacks are packed with junk, or their heat crossover leaks into the valley, and carbons up the lifter valley solid.

 

oh ok. Whats your opinion on oil restrictors in the mains? I enlarged the main bearing holes.