well if you get the stud out (or don't) you could / should drill it out such that you can use a tab nut and bolt instead of the stud
last hope may be an oxy-acetylene torch, heating the SV housing where the threads are (not the bolt head from underneath
)
good luck !
last hope may be an oxy-acetylene torch, heating the SV housing where the threads are (not the bolt head from underneath
good luck !