Building a little fun project buggy, a RedCat Hurricane XL. It came with most of the alumiunum parts already, and the rest of the upgrade parts are on their way.

With the project, I'm trying to keep it simple, no custom parts. Love to swap in a 3-speed drivetrain, but not for now.
What I need help with, is engine choice. I obviously want a something over the top. I was a click away from buying a Cen 7.7, before I wised up and decided to make sure it would fit. It won't, it uses smaller (18mm) mounting holes (like Ofna's), not the standard big block size. The Savage .46 is out because of it's dumb side exhaust, that I would never find a header for buggy use.
Anyone have ideas on like just some massive motor? .40+ or larger?