a quart over is enough to mess up most cars (especially when they get older). Oil tends to expand a little when hot, I fill it to specs then run it about 50 miles then check it again after sitting about 1/2 hour - on level ground, then add if needed. Be thankful you don't own Porsche,my old 930 used to hold 14qts of oil (air cooled) - after a few of those oil changes "OPEC" takes on a whole new meaning.