The only piston I have found so far that comes close to what you are asking are the Federal Mogul LPG pistons. The LPG pistons will get you 9.0:1 compression. I've gone thru the diametrical listing at Keith Blacks (Silvolite cast pistons) web site. Here's a link to the listing
http://kb-silvolite.com/spistons.php?action=diam The problem is the compression hieght of 2.09 inches. Without going to a longer rod lenght (which doesn't seem to exist) there doesn't seem to be an alternative to forged pistons if you want 10.0:1 or better compression.
If you do find something please let me know.
Larry
