What Compression With Stock Head Gasket?

If you wish to stick with a single shim steel type headgasket, with, say 0.100" shaved off the head, and flat top pistons,......make sure the surface finish is right on the head and the block.....too smooth, and it will blow....too rough, and it will blow.
I'd use Hylomar (spray pack) on the gasket, all the same.

http://media.supercheapauto.com.au/src/images/18035.jpg

ive been running a steel shim for 5 yeas with .113 off the head and .025 off the block with flat tops

I'm running a zero deck 170 with 38 cc chambers, with the shim gasket and no problems, even spraying over 200 hp nitrous.

wow thats like what... 12.5:1?