the gearbox will bolt straight up to the 2tg..... the engine mounts will be exactly the same also, and the exhuast will bolt up to the 2tg aswell.. the only things I can think of for doin a 2T -> 2TG conversion is getting a new top radiator hose.. and an electric fuel pump, depending on carby set-up.....
any more questions feel free to ask.....