I just dropped to 60 psi on cylinders 2-3 (the center two)
so I'm running on 1-4.
We did the following test, which you can do also.
Along with the compression test, squirt a little oil in the spark plugs holes, wait just a minute or two, and re-test. if the pressure increases more than about 20psi, then the oil just created a temporary seal for the rings, indicating the rings are bad.
on mine, the oil trick did nothing to improve the psi.
Next, if the culprit is not the rings, then the remaining options include Valves and the head gasket.
Its better news if its the head gasket, you can "band-aid" that thing for a pretty long time, like a year or more, with "steel seal"
http://www.steelseal.com/(just stay away from the products which claim to do the same thing and contain solid particles)
If its the valves, then its time for a cylinder head rebuilt or have your machined, "an as an added bonus" you end up with a new head gasket, and a new valve cover gasket.....
If we weren't both broke, we could afford to also send the head out to be ported, larger valves, and gasket matched.
However, for us mere mortals,
These guys sell a basic rebuilt head for $700, and a performance stage 1 head for $849.
rebuilt
http://store.nexternal.com/shared/StoreFront/default.asp?CS=vacmotors&StoreType=BtoC&Count1=527950465&Count2=445090889stage 1
http://store.nexternal.com/shared/StoreFront/default.asp?CS=vacmotors&StoreType=BtoC&Count1=527950465&Count2=445090889good luck, its not fun.