Bluedog,
The challenges of a series casting on this item is almost short of a miracle to the FE crowd and being in engineering/fabrication know the challenge/costs barriers. The WEBBER purchase will solve the problem and presently commercial engine fabricators with a track record are still receiving the blocks for build out. Individuals that attempt to purchase them to build out are on the bottom rungs of the ladder, especially due to the communication and problems created by the average "homebuilder", and it may stay that way for a while.
If and when I build "non-original" FE 427s for a replica, this is the block I use. Retail if you want one that we have in stock!
grumpy
admin@grumpysgarage.com