I overclocked my 83PSE, and Kerm has been urging me to post pictures. Well, here they are.

And a bigger version:
https://img.ourl.ca/rfg/overclock2.png
The black things are resistors. I could not find a 2.4k or 2.6k ohm in my limited collection, so I combined two to get as close as I could get, which ends up taking up quite a bit of space. I tacked them into place with some hot glue, as I am planning to get some SMD resistors that are closer to the ideal values pretty soon.
The clock speeds that I get now are:
5.441Mhz
14.213Mhz
17.33Mhz
20.415Mhz
I did not measure them before I overclocked the calc, so I am not sure if 14.2 is a normal speed for this one or not. When I upgrade to nicer-looking and more ideal resistors, I will put it back together and test the unmodified speed.

Thanks for finally posting! My experimentation yielded results suggesting the absolute value of the resistors doesn't matter. It seems to be more about the ratio of the resistor values. I almost felt like guess-and-check to get to the values I ended up finally using, so I encourage you to continue experimenting. That's why I decided to give mine that little 4-pin socket.

Epic job. It's nice to see other community members doing this.