Martin, Bentley says for an aircooled Vanagon the compression should be
between 87-131psi.  73 psi is minimum and no more than a 44 psi difference
between the cylinders.  Your compression test sounded kinda low to me too but
I am used to watercooled stuff and them aircooleds just aint as tight.  So
your compression tests look within limits.  It also matters if the engine is
warm or if you are doing a cold compression test.
Hope this helps.
Ken Wilford
Van-Again
John 3:16