Originally Posted by 64Joker
The following is my psi compression test on my 1964 327 cui engine:
No oil leaks, engine runs fine, idles fine, plugs are clean and dry, cooling
system runs a little hot (205 degrees), idles at about 180-185 degrees.
Should I have any concerns?
cyl 8: 165 cyl 7: 150
cyl 6: 160 cyl 5: 155
cyl 4: 140 cyl 3: 155
cyl 2: 155 cyl 1: 150
Generally the cylinder to cylinder pressure distribution should be about 10-15 percent. In this case the highest cylinder #8 at 165 is about 15% higher than the lowest of #4 at 140 psi. While number 4 is the weakest I'm not inclined to do anything about it as the pressure is still pretty good in whole terms.
Often opening an engine up creates more problems than it solves so unless there's a real need to go in, I'd just keep an eye one it while trying to delay intervention for as mush time as is reasonable say a condition of 20% difference to the highest cylinder or the real pressure falling under 120 PSI.