[exray]

I'm reading the schematic as 440 ohms. They put these resistances on schematics as a seat-of-the-pants reference for checking the transformer. You don't need to know the impedance unless you are searching for a replacement and then that info can generally be extracted from a tube manual.

Any possibility you are off by x10 reading the wrong scale of your meter? Something is definitely not right if you are only measuring 49 ohms. I would suspect a bad transformer if that's truly the case.