I have a 26 T, I was wondering what I have to due
I am assuming that you are running a distributor, so you will either have to add a ballast resistor to your coil or get a 12-volt internally resisted coil. Change battery to a 12-volt that is the same size as a group-1. Change all light bulbs, change generator to an alternator. Only solution I have for horn is a new 12-volt unit, we do not have anything to alter the voltage to make your old 6-volt work.