Farmall M oil filter base assembly plug stuck

[706man]

So on my 1951 Farmall M, the drain plug just below the filter is stuck. It was already rounded on the tool end. And when I changed the oil a couple days ago the rest of the exposed part of the plug crumbled. Then I filed it so it was a little flat and drilled and inserted a reverse bit trying to use that to break it loose. After a little bit of propane torch heat. Now the bit broke off and is stuck in the hole I drilled. I finally decided to just finish the oil change and call it good. Nothing is leaking. But now I really want that plug out.
Is it best to remove the whole filter base assembly and work on it from there? Can I put as much heat as I want to it without causing any damage? I am guessing I am going to have to keep trying to drill all the way thru the plug. It is very hard to drill thru that reverse bit that is stuck in the plug.
This plug is stuck bad. Already tried PBlaster and candle wax from the top end and hammering it and also heat. ANy suggestions appreciated. Maybe just find a new assembly to throw on there.

 

[DeltaRed]

Take the filter base off and get to work... Drill and whatever it takes. Easier to do the work in a vise or on a bench.

 

[Hayfarmer]

I had one of those plugs stuck on a 560, head rounded off. I eventually decided I didn't really need to remove the plug. With filter off I could sop rest of the out. I didn't really want to get to where you are now.

 

[560Dennis]

If it’s a must remove . Then weld a nut to it and back it out . Several videos on you tube to copy showing this