A tad bit of heat from a butane torch on those bolts will help to keep from snapping them. They are "glued" in from the factory with loc-tite. Don't need to heat it up cherry red... but just enough to help loosen the "glue". The heat from the weld I did really helped out in that respect. Of course, remove the plug wires and anything else that can be burnt from the torch. And be careful!!!
I actually put a small dab of anti-seize on the threads of the new grade 8 bolts when I rieinstalled them. No problem to report as of yet, and my truck does a lot of pulling between a 5th wheel and an 18 foot salt water boat.
Oh, I also never changed out the stock bolts on the other sdie. They are just fine. Truck has 125,000 miles on it.
Gary