I can't give you numbers but for better performance the thin gasket is a good
deal. You can measure the old gasket with a micrometer and probably tell
which it was. But if your headgasket is good and you don't have any other
reason to tear down, I'd suggest waiting for stronger motivation. It is a
job that takes time and energy and like any engine job, you ALWAYS have the
opportunity to screw something up, which if you can avoid, is all to the good.

As in any headgasket replacement you want the mating (faying) surfaces good
and clean. I usually put a thin film of grease on the headgasket (and many
others). Some of the Volvo gaskets had some kind of encapsulated adhesive
in the gasket, possibly a thermoset, so that the residue is really hard to
remove. The grease keeps it from sticking so bad and seems to help the seal
also. You should get an upper gasket set because you'll be taking off
manifolds, etc, and maybe doing a valve job. You'll need most, if not all
the stuff.

Since the IPD garage sale is 2000 miles from me I'll probably pass it up
AGAIN. Would like to be there for one but no idea when. No wheels to sell
or donate either. Sorry....
--
George Downs, Bartlesville, Oklahoma, Central US