I had to do the same thing when I upgraded to an 80lb Minn Kota...
Installed Marinco 70A Trolling Motor Plug & Receptacle, 6 G wire, single 60A breaker.
FYI if you need wire, check out https://tinnedmarinewire.com/wire/
... they will send wire with your colors, add whatever size lugs you need, heat shrink, etc.
On a side note, I had an older MG motor that started cutting out at high speed, found a melted wire in the head. Cut and re-soldered, it was fine after that.