sb are not to bad,got to watch the end studs
the smaller socket tapped on is one good way,I have done that most times with them comeing out
yes a torch and red hot they come out easy,I just run a couple beads withthe wire feed welder to get a BB stud red hot..it came right out
if you had to,you could torch the head off to remove the manny,then it would leave a good part of the bolt sticking out to grab with vise grips
start spraying a couple days head of time with PB-blaster and run the engine some to wick it in good,that helps with rust for sure
the 2 end studs are in water,so be ready for it to drain if they come out
I use the copper rtv on the mannys and head with no gasket on sb,never have a leak with them,let cure over night and no more leaks
buff them down with a scotch pad and grinder wheel to clean them up nice and stick them
IMO,I would undo the head pipe first then remove the manny,spray those bolts down good with blaster as well
good luck and hope none break