A magnum block is stronger than any production LA block except maybe a TA but even then I think I would take the magnum. It has stronger metal you can feel when grinding clearance for strokers, it has some more meat around where the mains meet the pan rail and some other little goodies. I also see in those pics he tied 3 of the cam bearings together with a home made brace since he was not using the factory roller lifter set up.