It’s a billet block that they add water jackets . Contact al alguire
lol..The Chevpar stuff is a museum piece for sure. Pretty cool to see though, the outside the box thinking it took. Dave Koffel still has a couple of the converted deals in his garage, not for sale just a couple cool pieces of history.
CN will make you just about anything you can dream up for sure but at a cost for sure. Pretty sure the Koffels use a KB block with the TS heads in the Lake Erie Monster with the blown TS headed engine they have. Also have a B1MC version