What do you guys think this date code is? 1 6 68 or 1 6 66. I cant make up my mind. http://www2.freepichosting.com/Images/421509206/0.jpg

My "best quess" is that it's an '8' - based on the slight indentation on the left about mid area and the faint circle on the upper right.
Can it be Media Blasted with a fine material like Borax Powder to bring it out better?

I may try that or pecan shells. It's a 3917610 intake in pretty good shape. I bought it thinking it was an original 67 z/28 piece, but now I am not so sure. Either way, it looks the same from the top!

If it's a 610 intake, the last digit is probably an '8'. But, like you said, once the intake is installed, the date is no longer visible so the 67-68 intakes are indistinguishable from one another.