Stainless valve in cast iron guides,issues?

Hi , I wonder , have anyone heard of , or have experience of that stainless valves dont go together with cast iron guides . I was talking to a machinist who says they will sort of grind together , the two materials dont mix well .? And you must use bronze guides . Another machinist says its ok if valve stems are chromed , arent all stainless stems chromed? Anyways , opinions or experience of this . Cheers Ubbe.