For the LA 360 the head bolt torque is 95# with bolts lightly oiled ...Don't know if magnum is the same or not
As for the freeze plugs I always use a little sealant on them for two reasons ...1 it helps to slide them into the hole and 2nd it fills any imperfections in the casting. I prefer using Aviation form a gasket. This is the black gooey stuff that comes with a brush built into the cap (similar to Indianhead shellac)
It has always worked for me for the last 35 years ...LOL