• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Montgomery Ward WG-2854A

It is going to be possible, but the main question is whether you just want to be able to link it to an external sound source, or you are going to adapt the chassis so that it is a standalone amplifier.

If the latter, then you will probably want to drive different speakers, and then to get the most out of it, the circuit may have to be adapted so that you get the frequency range to appreciate those speakers, and then it is soon descending into a re-design, since a change in one place usually requires a change in another.

What is your goal?