What If Build Ideas...for Land Speed Racing

So, lets build on the comments above for a min. Lets say it was decided to build a 400ci B motor. Remember, WOT for 5 miles at a time here....

What block?
Is the factory casting good enough?
Aftermarket? Does it need cross bolted mains?
What rotating assembly? take it to 451 (seems like a go to size) with Molnar parts as an example? Calies?