906 big block valve ?

Is it possible to use oversized 2.11 intake valves in a 906 head without hitting the flat top pistons on a untouched 383 HP motor? Real MILD upgrade on the hydraulic cam and .035 shaved off the heads- stock rockers and pushrods. This is what the machinist want's to use instead of reworking the guides and I have concerns -- comp cam # 21-223-4 = 477/480 lift