Yikes, is he going to machine the block from that aluminum billet??
That's easy, you just chisel away anything that doesn't look like a block

Billet blocks are starting to become the new wave for the super high-end cars. Steve Morris builds some of the baddest engines on the planet, but I think even HIS custom dyno will be a challenge to hold this one.
Kirkham Motorsports did an FE billet block some years ago for one of his AC Cobra builds, but I never heard or saw how it worked out in running condition. He started with a 386lb block of billet, but the end result doesn't look much like an FE block. Still, it takes all the normal FE parts. If someone wants to waste some time, the videos can be found on YouTube.
http://youtu.be/8KLNJ8d8Vqc