I have a 1977 450SEL that overheated and blew both head gaskets. I have removed the heads and taken them to a shop to get them checked. They are reporting that the heads have 0.015 inch warp (which translates to 2.03 mm) also they are saying that the heads are below minimum thickness. I checked the engine service manual and they allow 0.08 mm (0.003 inch) of warp. The from "new" head thickness reduction allowed is 0.25 mm (0.010 inch). While the manual says that "a slightly distorted parting surface will adapt again to cylinter head when tightened" in section 01-418, I am concerned that the amount of distortion measured is more than "slightly".

Any thoughts or guidance would be appreciated. I really don't want to spend a significant amount on the car due to the body having some corrosion issues.
Thanks,
Lee