The Nuyten Block is begun from a solid hunk of billet.
The Root block was a cast block with much beefy ribbing in the valley area.
I think the Trick Flow block was also a cast block.
I know at times Sonny had used both the Root Blocks and the Trick Flow blocks.
I also think the new Dart Aluminum block is begun as a casting and then machined to spec. Not positive yet on that though.
His question has been asked on several different boards, and I know I have replied to it on three of them.
I also suggested to him on one board that buiding a 706 cu in engine is not a wonderful idea for the novice builder. It can be done but there are lots of things different and much more time consuming. You better be up to snuff and dod all your i 's and cross your t's and use the spell check several times, if you get my meanings.