Lost power all of a sudden. 273 commando.

Let's hypothesize for a moment..........you've checked timing, advance, carb, reasonably sure of your ignition module, alot of stuff and nothing is jumping out..........let's say that the engine is still running just fine as it always had, could there be a problem with eather, or both, converter, tranny? Engine's making power, just not making it thru the drive line.
It's an idea......