There is a C2AE-6015-J 406 block for sale right now on 332-428 Ford FE Engine Forum in the classifieds for $850. See the "FE blocks for sale" Ad by DSC Dennis. There are numerous 428 and 390 blocks listed as well. Ad also says he'll accept time payments which is a nice option. HURRY!

Seems like a good price. The last few I've seen have been $1000-1500 bare blocks.