Highest flowing sbm heads?

Valley Performance and Machine Service’s 376 cid Mopar Engine

"“We had the factory stock block cryogenically treated in Grand Rapids, MI, making it 30 to 40 percent stronger than factory,” Barna says. “I’m a believer in that process. We’ve been doing more and more of that lately.”"

I did some cryo treating of 7075 alum parts back in the day, and that process is no joke. Really helps make materials more consistent and less crack prone. Steel tends to gain a ton of strength too.