Help 1972 datsun 240z exaust manifold stud 6th cylendar

i have this car, see/ a 1972 datsun 240z. as far as i can tell this is the only thing that is wrong with the engine, the exaust manifold stud head is broken clean off, can anyone give me the best way to go about fixing this. It would be much appreciated.
Ken, the Z-kid

You can buy reverse drill bits inexpensively.. harbor freight has them. This is assuming you can get at it.. try drilling out the center to use an "easy out" if necessary, the reverse drill bit might just twist it out for you, had that happen many times. Good luck!

the only thing that i need to know is how to go about getting a new one, i think the tool will be easy to find, but im not sure about the actual stud.