Everywhere I've called today has told me its discontinued

 

There isn't a housing gasket. There is a slotted o-ring that fits around the
outer edge of the thermostat.

 

The o-ring is GM PART # 12551507 and is still available.

It normally comes with a new thermostat. As caldercay said, there is no other gasket used. The housing is precision machined to fit without a gasket.

 

the paper guy?

 

No paper guy. You need the o-ring guy that fits around the lip of the thermostat.

 

Paper guy? There is no paper guy-only the o-ring.

 

So..... you're telling us they discontinued a part that doesn't exist?

 

Yep - better known as, predisposed obsolescence.

Here's a photo of an LT1 thermostat *with* the o-ring on it and an
extra o-ring sitting on top of the thermostat - notice the groove on
the ID of the o-ring. This o-ring substitutes the "paper" gaskets as
required on other engines. (sorry for the fuzzy photo).

http://picasaweb.google.com/calder.c...65708326938450

 

I just took mine apart to replace the Water pump and it was just Metal on Metal.

 

Hopefully, you understood my attempt at humor with Rob. I know what the o-ring looks like.

Did you ever look at the photo of the t'stat on Shoebox's page:

http://shbox.com/1/tstat.jpg

 

Yea, Fred - It would be a cold day in he|| before I would correct you;
your deep technical knowledge is beyond what I have to offer.

The only comment meant for you was the "predisposed obsolescence",
being in agreement with you. The rest of my explanation and photo
is for those lurking and the OP.