Looks like a duratax thunder quake. They had a nitro quake too, but it had c-hub vs pivot ball axle carriers. Both were nitro engines, just different names with the Thunder appearing to be the more basher one (2 speed/reverse) vs the nitro being for "racing" with a single speed center diff.
Neither of which ran OFNA engines, so someone else put that on there.
Although, now that I'm looking closer, the tank doesn't match yours... neither does the center brace... CURSES!
Sorry, don't have a clue.
You do appear to have a big block, so it's probably 1/8th scale. You also a shifting mechanism, likely for forward/reverse, so not a "truggy" as those usually have center diffs which would make this a MT/Monster Truck and you have c-hub axle carriers. The arms look beefy and possibly has holes for sway bars.. OFNA engine, but that could be someone elses doing, if not, it's one of OFNA's trucks that I"m not recognizing. You can look over all the manuals OFNA has online to see if it looks like anything: http://ofna.com/manuals.php
I looked at the obvious ones with MT/Monster in the name and none look like yours.