Quote: On a BB you'll be lucky to get it 1/4 filled. Take the filter and lay it on your bench and you'll see that the oil will drain right out of the outer row of holes.
An antidrain back valve prevents oil from reversing out the outer row of holes. You DO have to make sure there is only little oil visable past the threaded hole-which is easy tip the filter and it drains through the media into the case. You can even do this on a slant 6 (leave no 'visable oil' if you're quick
