Are those blocks pre-drilled to oil thru the block or are they factory set to pushrod only oiling and you need to drill the passageway? The next time I pull my engine to freshen, I may drill mine to oil thru the block to open the door for using LA style heads on it. Could actually let it oil both ways as long as it didn't affect the way it oils everything else. I have been wanting to do that but it's still as strong as it was brand new even after going into it's 6th racing season without haveing the block or rotating assembly touched. I did change cams last year alone with Hughes shaft mount marnum style rockers. Other than that, it never even had a valvecover pulled off. Thats durability at its finest! I even thing the older it gets, the faster it goes. I love the magnum stuff.