The Joe Simon Mod turns a Guv'nor MkII into a MkI, or perhaps even something better than MkI. I'm demonstrating it through a 1973 Marshall Super Lead and a 1971 Marshall 1960B using a 2013 Gibson SG CS Standard Aged.
The Joe Simon Mod:
https://www.youtube.com/watch?v=UTsm2bsuD_Y&feature=youtu.be
https://www.instagram.com/joesimonlabs/
My demo of the Marshall Guv’nor MkI:
https://www.youtube.com/watch?v=EK2RkzF67XU&t=89s