3 speed to 4 speed

hey there i have a 70 225 slant six 3 speed on the floor car, and i am wanting more info on a good 4 speed swap the car will be built and turboed and would just like another useable gear, also does anyone know if when swaping over to the 4 speed does the shifter come out of the tunnel through the same opening as the 3 speed ? thanks guys