5k blower motor removal questions...

[OorQue@aol.com]

As some of you know, I unexpectedly got the 5k I sent off to the junk yard 
back recently -- it's a long story -- and I have decided to pull a few more 
parts off of it before sending it back to the salvage yard a second time.  
Today, I'm trying to remove the blower motor assembly but I'll be damned if I 
can break loose the seal holding it to the firewall ... I've tried using 
heat, bent hacksaw blades, you name it, but it's not budging.  I had somebody 
else install a new heater core for me shortly before it was totalled three 
years ago and I'm guessing they used something other than the factory gasket 
material because this thing is thorougly stuck.

Any hints?  If push comes to shove, I know I can definitely get it out of the 
car but the idea is to keep it intact so I can re-use the parts rather than 
to trash them in the process ... any BTDTs or helpful hints will be 
appreciated.

JG