I am in the process of building a 400 sbc and have been lookin for a head shim with thickness of .0015 to .0018. I havent had any luck finding anything. Is it possible to get a shim that thin or am I wasting my time looking? The smallest I have been able to find is .0028 from, I beleive, Cometic. Do you guys have any ideas where I might be able to find something or any ideas other than taking a little off of the deck height.