I think I'd set a pair of 0.125" gaskets on it and see how much gap you have between the china wall and the bottom of intake, planning to use black silicone to seal the ends, no gaskets. You could even torque the intake with the gaskets and ensure that you have a slight clearance on the ends. If it's too tight to ensure that your intake gaskets are going to compress to seal, then I'd take a cut off of the bottom front & back intake surfaces, where they mate to the china wall sections, bolt is on and run it. Tell your machinist what gap you have between heads & intake, and let him figure the needed cut from the bottom to get the surfaces mated.