The Big M block also has about the beefiest billet steel main caps on the planet. They’re needed to hold the Scat rotating assembly as it was regularly spinning to seven grand during testing and cranking out well over 700 hp. That number crept over 800 horses while trying out a combination with small-block rod journal sizes until, um, the crank broke. Mike Stine decided to stick with the big-block journals after that. Smart move.