2000 Ford Explorer 4.0L VIN X Head Gasket Repair?

I have a 2000 Ford Explorer 4.0 L Vin X. I need to replace the head gasket on it and I'm down to the heads and exhaust manifold. I'm trying to get the manifold off but the nuts on the top of the manifold are stripping (and they're very sexy) and I can't split them with a nut splitter. So I tried removing the bolts at the bottom of the manifolds. No dice. Stuck on just as tight. I've sprayed a hell of a lot of PB Buster on them but it does nothing. I need advice on what to do now because I need to fix this car so my family won't be short on cars anymore.

You need to heat them up but good. Ideally red hot with an oxy- acetylene torch. But a Maap gas one from home depot might do the trick. Be careful & have at least one fire extinguisher at the ready.

If you didn't open up the fuel system I would have said torches (or a butane torch for pipes in the house would take longer but would work) but how far you said you have gone you in fact did open up the fuel system. Another thought is taking a bigger nut that can go over the other nut/stud/bolt and weld it to it. That will heat it up and give you something that is not stripped. Or you could use a grinder or cutoff wheel too just wet a rag and wrap the open fuel lines