Not a lot of options on the 350.
You can zero deck the block, mill the heads a little, which might get you to where you want to be. There's only one stock piston available anymore the 350, otherwise you could go with a custom piston that would raise your CR. (There was an article a while back in one of the magazines on how to modify a small block Mopar piston for use in the Pontiac engines, if want to go that route.) Or spend a lot money on aluminum heads.