Compression question

["Eric Frisbee" <efrisbee@charter.net>]

Hey folks!
        I just ran a cold compression check on my '70 2000 and.... seeing a
9 PSI difference between the front cylinders and the rears  #1- 172, #2-
173, #3- 181, #4- 179.   I haven't adjusted the valves recently, but that's
definately on the list of things to do this weekend.  Any thoughts out there
as to anything else that could be causing this change from front to rear
cylinders?    Thanks in advance for any thoughts!!!

Eric