Well, 84 x 48 - but yes, I'm just downloading my project from last year so I can put it on Github, then you can see how I did it - I'm sure there's many ways.
https://github.com/1888games/Horace3310
Don't remember exactly how I did it, you'll need to set a custom view resolution of 840 x 480 in the Game tab. To be honest if I was doing it again I might do it a different way, but I'm probably doing this year's jam in something else.