I have just replaced the intermediate pipe on my Westy and the stress of removing the old one has caused a crack in a primary pipe at the flange. Now it is time to tackle replacing the whole system. What sort of hell am I entering by pulling the exhaust bolts from the heads? So far I have only scrubbed them off with a brass brush and sprayed them with PB blaster a few times. Will heating the bolts with just a propane torch loosen the stubborn bolts or should I have the neighborhood welder hit them with the oxy torch?