Can anyone tell me where to find a chart of compression psi? I am looking to rebuild a few engines I have but don't know what the compression test should read. Is their different specs for different manufacturers or are they all the same? Thanks for any help in advance!!!!

Unless you have a way to spin the engine at an exact RPM for each test, I don't think you are going to have success with compression tests.
The only way I know to check the compression is the 'thumb gauge'....Roll the flywheel with your thumb against the compression with gentle, steady pressure. If it bleeds pressure off quickly, then it doesn't have good compression.
Also, another 'gauge' of the overall health of the piston/sleeve fit would be the degrees of revolution in the pinch. Without the plug in, roll the engine through the pinch zone and see how many degrees the flywheel turns. In a worn out engine, you will barely feel a squeeze, where a new engine has significant resistance through the pinch.
Nothing scientific, or easily put on a graph...as far as I know.

Thanks AVG Joe! When you buy new motors or work on old ones, they don't have a compression range that is good or bad? Why do they sell a gage? I just don't feel confident with my knowledge to be able to say weather or not a motor is good or bad.