They are all so high that I would lose no sleep over the differential.
If you have a running truck, if you have not changed the oil/filter, do it.
I'm a shade tree mechanic - set the timing and carburetor mixture to maximum vacuum using a vacuum gauge at the wiper-vacuum port on the intake manifold. Adjust the idle speed at a slow/smooth idle (or, 350-500 RPM, if you have tachometer).
Then, go for a long drive.
Then, check the compression again.
Then, report back here.
Maybe, then, congratulations from all will be in order.
