[Vwdiesel] freeze plug stuck - installing block heater - tips?

[Will Taygan]

1991 Jetta Ecodiesel.

So I've spent 2 1/2 hours with a 6" cold chisel and a hammer and various
screwdrivers etc. trying to get the freeze plug out (yep, engine in car)
I'm a bit nervous about cracking the block, but I'm also nervous about
getting the @#*& freeze plug out!

Should I just get a bigger pry bar?  Soak it in P'Blaster? The hole is
big enough for my thumb to go into the first joint.  Would chiseling it
in half (top to bottom) help?

Thanks,

Will.