I thought I saw that too. AFAIR, Chrysler never made a skirted CI block, except the the Pro Stock block that David Nickens got stuck with.
It's a pretty big power killer to skirt the block like that. That's why I can't imagine anyone in NASCAR would even want that. If it's aluminum, that's the block the made for the 410 sprint car stuff. Those guys care so much about weight the drivers take laxatives so they can crap before the main. True story.
