The worst case scenario would be that there was not enough airspace for the pistons to move down in the normal rotational cycle and liquids don't compress (blow rings, gaskets, and or crack critical things like heads or cylinder walls). This is the extreme and not likely from a few cc's extra. Ideally you might get some blow-by, smoke, loss of power and nothing more. Folks in the old days who didn't want to trust the oil pumps would remove the oil pan from their Yes Studebakers, and make a determination how high the oil would have to be for the rods to dip into the oils and lubricate things sans oil pump. Just right ok, too much, gridlock. I'm sure you are fine but I'd try to avoid the quandry in the future. Tom