Ok, so first off, I mis-read the specs of the original engine pretty horribly. It's not a 1400cc engine, it's a 1400 CID engine. Big difference! That would certainly explain the dual bolts on the con rods, to say the least. And as for the vehicle source, it wasn't a car, bike, or a plane... it's a tank! A German Panther tank, to be exact, circa 1944. The engine is a Maybach 230. Here's the site with the thread for the curious:
http://corner-carvers.com/forums/showthread.php?t 756
(For those of you unfamiliar with that particular site, it's an automotive forum generally dedicated to professional and amateur racing, not of the "on street" variety. Lots of... shall we say... "dominant" personalities there, and while they do come up with some interesting stuff from time to time, even by their own admission it's not a particularly friendly and sociable place for those who aren't already in-the-know.)
So much for my ballpark guess on torque specs for the thing. Probably also ruins any chance of finding some kind of official tool name for it, but at least it gives a better direction for research. Tank engine guts... any war machinery historians out there?