Bicycle Mechanics - Stuck cog removal advice

(Please excuse the double posting; I meant to post this here but mistakenly posted it the Classic & Vintage forum instead, so I'm reposting here.)

I've been trying for several days to get the small cog off my Suntour Pro-Compe freewheel without any luck. I tried a freewheel vise and chainwhip, but couldn't budge it. All I was accomplishing was dragging my workbench around the garage. So I took it to the LBS and they couldn't get it off either. They're usually pretty good at getting stuck components loose, but this time it was no dice. One of the mechanics told me he tried so hard he was afraid he was going to break his tools before he gave up. I brought it home, left it soaking in a bowl of Liquid Wrench overnight and still ended up dragging the workbench around the garage again. So I've had it soaking in the Liquid Wrench for a few more days, and tonight I'm going to pick up some PB Blaster on the way home from work and see if that does any better. I've also bought one of those little pencil-thin butane torches to see if heat will help break it loose.

Any advice on how to proceed? I don't want to damage the cogs, because they're in great shape and the whole point of this exercise is to remove them from the worn-out freewheel body and put them on the NOS body I bought to replace it. Should the torch be applied to the cog, to the freewheel body, or both? How hot should it be? (The torch is supposed to reach 1500° F.) Do I need to try to remove it while it's still hot, or after it cools? Should I use the PB Blaster on it before or after heating it? (I assume that stuff is flammable, and don't want to start a fire!)

Any advice will be appreciated.

I generally don't use the torch on any part I actually want to keep afterwards. But if you're going to use it, PB Blaster first, then torch. It'll smoke, but should be fine. Can't say what it will do to the rest of the assembly.

I generally don't use the torch on any part I actually want to keep afterwards. But if you're going to use it, PB Blaster first, then torch. It'll smoke, but should be fine. Can't say what it will do to the rest of the assembly.

Maybe I'd be better off with trying cold rather than heat. In any case, I'll try the PB Blaster by itself first.

Or maybe I should just replace the whole freewheel. I've already wasted a lot of time on it that I'd rather have spent riding.

pictures?