No disrespect to Alexi or any of the other guys at Ilmor, but it's BS to say the stock block cant handle 700 hp or less under the stresses typically seen on the water or on the street. As mentioned, one of my Viper's is making twice this power and the other is a dedicated road racing car... and it does see PLENTY of stress every time it's used... no cruising at 3500 rpm or idling through no wake zones with that engine! Likewise, I know of countless track and race cars (including factory cars) using the stock block and I've never heard of a single BLOCK failure!!!
Now I would agree there's some issues with oil starvation under the #5, but there's no need to build a new block to address that!
Regardless, I agree Ilmor has done a fantastic job with converting the V10... I just dont agree with your comments that the factory block has to be replaced to withstand marine absue as it's a fairly stout piece and should have no issues withstanding 'only' <700hp.