I am mounting a 1/2" plate between the engine/trans, what issues am I looking at in regards to the starter? Do I need a starter with a 1/2 longer nosepiece??
It seems to me you'd want to be worried about the input shaft legnth on the trans. The starter bolts to the block doesn't it? and the flex plate mounts to the crank, so no matter what you put between the block and trans the starter/flex plate alignment will remain the same. But now you have an input shaft that's 1/2" too short.
As far as the cav plate hardware, try Glenwood Marine (http://www.glenwoodmarine.com) or Rex Marine (http://www.rexmar.com)