6.93 is possibly a 10.9XXX, probably an 11.00 something. Why is that so hard to believe? It runs pretty good. The thing that would make me say it runs good for what it is is the hydraulic cam. The bore size wouldn;t be a thing that would make me raise an eyebrow. Consider a 406, thats a .030 over 400, at 4.155 bore. Lots of 406's will run 10.90's easy. Your bore is 4.25, thats .100 more than a 406, plus, its 48 cubic inches bigger. So, the bore size wouldn;t be a big deal. Plus, the big block, the valves are canted, and open away from the cylinders, un-shrouding them better.
Frank
Advanced Performance
www.get-ap.com