From a small DIY guitar electronics book which I bought
in the mid-1980s.
I remember building this for a friend at that time.
I think it sounded halfway between an overdrive and distortion.
The circuit obviously has to be modified to be of use in practice.
I think R6 can be replaced with a 500k variable resistor as
a Distortion control.
Another variable resistor will have to be added as a Level control,
I guess at the output after C5, or after Pin 7 of IC1.
A tone control circuit could be also be added in.
The bypass switch of S2 could be replaced with those Boss
flip-flop type FET switching circuit.
S1 could be replaced with an input jack with a ganged switch.