The 356 Porsche torque specification for this nut is 55mkp (397 lbs ft). Don't take a chance on your socket slipping off of your fifty year old used castle nut that has had the corners knocked off of it by butcherous shadetree types over the years.
Start fresh with a new axle nut and you'll be sitting pretty for the next fifty years.
Need a little help torquing that 356 Drum Brake axle nut? Check out our Torque Dude, 36mm NUt Management System.