Nominally, the pushrods would be shortened by that same head milling amount, in order to put the lifter pistons in the approximate center of their travel. The pushrod angle would make the change at the lifter a few thousandths less but not nearly enough that you could avoid changing them out. If you put stock length pushrods in, I'd expect all of the lifter pistons to be bottomed out and all the valves to be hung open.
