I just got my E31 head back from the Z Doctor. The head has an Isky Stage II cam with .480 lift. The head was not shaved other than clean up. We put 260 Z exhaust valves; 35mm vs 33mm (1.38 in. vs. 1.30 in.). Intakes are 1mm oversize (43mm vs. 42mm ; 1.69 in. vs. 1.65 in.) Is there any mods that have to be done to the block for clearance reasons, or should I be OK as is? I know eyebrowing the block will let it breathe, but is it necessary for clearance?