I was looking into that. I have everything for my top end rebuild specifically for an LA small block. I know oiling for the magnum blocks are vastly different. What modifications would I have to do to make a magnum blocks compatible with an LA top end?
I would sleeve that, bore to .030 and build what you have. Add a 4" crank, and you could have a nice 416. As far as the magnum question, use oil through lifters, hollow pushrods and a set of PRW rockers. It's that simple. Nothing complicated at all.