OMG, just buy cycling weekly this week or read a book just for the basics.
SFB is right you could overload your water handling and sodium capacity.
Basics is that consuming more carbs increases stores of glycogen and atp in the muscles and liver-these short reserves give the explosive energy you need.
(Personally I’d be training the lactate threshold and recycling for long events of over an hr but it depends on your metabolism/genes.)
As glycogen attracts water, hence if lots of glycogen storage/carb loading is stored it will also have water with it hence check your weight before carbo loading and during and before the event to see if it is successful (you should gain 2-3 lbs).
Your muscles might look toned too.
I wouldn’t cut down on my proteins though or drink more than 2 litres of water. It varies from person to person and activity. I think you use 1.5 litres a day but if you study sports science and apply it just don’t over do it.
Just carry on as usual but eat the correct food for extra carbs.
It can stress the body so don’t blame me if you kill yourself.
Even with all the nutrition, training, exercise and diet you can’t beat natural ability – sorry!
But done right could give you the edge over yourself.
Hope you do well and enjoy the race.