George wrote:

I'd try hammering in a torx bit or another tool that is close to the
same shape. I've heard of people having good luck with that JB Cold
Weld - I have two tubes but haven't used it yet myself.

I'd be real nervous about welding on a fuel tank that may have fumes
even though the gas is old.


First off, my thanks to all of those who responded with ideas, all of
which were helpful.

I ended up grinding down a half inch extension to a fairly tight fit in
the munged up
hole. PB blasted the threads on the plug four or five times.
Hammered the extension in, attached an 18 inch breaker bar, and
went to turn it. Unfortunately the corners on the inside of the plug
started to
turn up and out and the plug itself never moved. The recess in the plug
is
fairly shallow.
I think someone must have tightened the hell out of this plug years ago.
The tanks are 3/16 steel plate, and the plug is mounted in a very heavy
boss.
I think that an impact extension could be mig-welded into the plug
and it could be turned.

The only problem might be my hands shaking too bad to get a decent bead.

My neighbor said: "Go on and weld the damn thing. Hell, she aint goin'
to make but one bang!".