My heads were milled-effect on compression ratio?

I just had .040" taken off a set of 318 heads to accommodate the FelPro blues. Machine shop said .040" off will not do much and intake bolts will still match up. I port matched the heads to the intake and it was off height wise just a tad from before the head cutting. I tried to find a set of steel shims but they are hard to find.

Good luck and keep us posted.