I believe most stock V8's were upto 150 psi cranking pressure. Remove all spark plugs or the engine will not spin fast enough on the starter to get an accurate reading. Anything from 130ish-165 is acceptable if nominal is 150. A bad valve guide or leaking valve seal will not show on a compression test. A worn out engine with leaking rings will show low on all cylinders. Add a little oil through the spark plug hole. If compression is still low, it is a bad valve. If it comes up to 150 or so, it's bad rings.