Bends in a pipe create more restriction than a little extra length. An extra 18 or 20 inches including one or two gentle bends to make the exhaust pipe cross over to the passenger side wouldn't make much difference on those engines since they ran through conventional mufflers anyway. Unless every cylinder was fitted with a pyrometer and an oxygen sensor I don't think even the world's best mechanic could state that 3 cylinders were running better or worse than the other 3.
