Removing cab mount bolts

[NJ C10 Guy]

I'm almost at my wit's end with these. My truck is in relatively good shape, with what I consider minimal rust for a 29 year old truck. I can not break the front cab mount bolts loose. I've tried a regular ratchet, breaker bar, and a cordless impact that puts out 133 ft/lb of torque. I've used a can of PB Blaster and I've been spraying it regularly. I even hit the bolt with a torch and hit it with a mini sledge to break up any rust on there. Still nothing. Oh, I am making sure I am backing it out and not tightening it. I don't know what else to do. I need to get this part of my build done, and it's driving me up a wall. Next up is to use an air impact. I really don't want to have to cut a hole in the floor, because I'm not a great welder and my floorboards are in great shape.

With the PB Blaster, I am spraying at the top of the cup where it meets the cab. Am I spraying the wrong thing? This is really killing me.