In the past I've turned down some big logs, I mean 4+ foot diameter. all of them were white oaks, one was a walnut, riddled with metal. The walnut had more purple heart than natural heart. Hind sight, I would open that rascal up, back then I did not know of these forums, youtube, or anyone that had experience with this type of work. Turns out folks have been splitting large logs for years, and I've seen some of it, just too late in the game for me. If it were me now, I would layout a cross hair on both ends, after locating what faces I wanted, snap a line and get after it. worse thing that can happen? waste some time and fuel, and gain some firewood.