The factory 12-point driveshaft bolts are coated with pre-applied factory loctite
Heating things coated with loctite to 400degF kills the loctite bond.
400degF has NO effect on the strength of the steel, but can FRY nearby parts like the pinion seal the pinion seal dust shield (the plastic piece on the back of the pinion flange)
Grease boots on the U-joint cups, etc...
So be CAREFUL with where you apply that heat.
Personally I wire brush the threads CLEAN and apply Neverseeze to
the threads before reassembly and I've still had a few "stick", so I am
mystified why Ford thought loctite was needed.
There ARE six point bolts... the cap screws on the yoke straps where
the two halves of a two piece driveshaft joint at the Halfmoon yoke
just behind the center support bearing.
What scared the hell out of me was seeing the printed torque spec on
those tiny bolts. (5/16" heads) where the early manuals listed it as 60-ish ft/lb...
it should have been 60-ish INCH/lbs
AD