Not a big block, but I recently had a small block /L31 longblock replaced through Advance Auto Parts for around 1200 bucks. 2 year warranty.
I believe ATK is the supplier for them.
Nope...he's on the money. Gen3 coyotes are the big money especially with the 10r80 trans.
He may have better luck contacting Power By the Hour or Rare Fab in Florida.