Hello, I have a question, I enlarged the oil passages on my 400 but I was wanting to know about the oil holes in the bearings. If the passages are the only place that the enlarging is done then won't the smaller openings on the bearings negate the improvements. Should the bearings be opened up to the same size as the oil holes to match? I know that this may be a simple question but I just want to know. Thanks Ron
All you should be doing is making sure the oil hole in the bearing is not masked in any way. Do not open up the hole in the bearing.
The main oil hole is plenty big to supply the bearing the way it came from the factory. The problem is that the main feed comes off the lifter galley past the cam bearing and gets partially blocked. Enlarging the passage hole increases the area past the cam bearing and increases the amount of oil that comes through. I wouldn't drill the bearing.
