The inner and outer nuts are cheap. I heat them until they are red hot and then pour water on them. You might want to do this several times. I even go so far as to cut them, but you have to use care not to cut into the stud. I have 1" impacts and one of these for really stubborn bolts.

http://www.protoindustrial.com/en/industrial-tools/Proto/Precision-Torque-Tools/Torque-Multipliers/600fcaaf-5cc5-4579-8d41-9d9a9d242446_Proto%C2%AE-Torque-Multipliers-3200-Ft-Lbs/#

But without heat you would probably break a stud. I still have one of these around somewhere.

https://www.amazon.com/Ken-Tool-Power-Wrenches-3-Pc-Model/dp/B00132AMF2

But on a really tough one, 3 to 1 leverage is really not enough without heat.