303 Rocket olds compression test #'s

hey all...just finished a compression test on my 53 olds 303 engine with an automatic trans. i figured i am about 39-50 feet above sea level, and its 84* outside...ahh sunny florida! anyways..here are the numbers in psi according to the gauge. it also had a kPax 1x100? but here they are in psi...I could not really find a reliable chart to exhange psi to Compression ratio...and i know it depends on elevation yadda yadda...but if someone could tell me if these numbers are any good...obviously some are lower than others...and i did read somewhere you want psi to be 15-20x the compression ratio....in this case the factory CR of a 303 rocket in 1953 was 8.0:1 so this does indeed look low....

anyways...tell me how bad they really are...

Cylinder number psi
1 80
2 80
3 75
4 95
5 95
6 90
7 110
8 102

thanks for any info....

 

Was that a wet test (oil in cylinders first) or dry?

 

it was a dry test. i might try a little oil in that #3 cylinder and see what happens...
using a "rented" compression tool from autozone.....

 

Low but even. Indicates a worn engine but no disasters. If a shot of oil brings it up, the rings are bad otherwise the valves are bad.

How many miles and how is your oil pressure? It seems like someone has a motor job in his future.

 

Not sure if others will agree or not, but when cranking the engine for a dynamic compression test I block the throttle all the way. One time for all cylinders. This allows the cylinders to draw as much ambient air as possible. Then that air is compressed during the test. But, DO NOT forget to undo that block as soon as you finish the test. Otherwise, when you start it......uh, not so good. I'm pretty certain some will disagree with this procedure.
As mentioned, the numbers you came up with are a bit soft, but no too bad for an engine that's been in use for a while. Another thing you might try is to use a different tester. You may be surprised at the difference. Keep us updated if you do this.

 

Thanks for the replies. She has had good pressure never dropped. Maybe a quart low. But otherwise always has oil pressure. Just started running real rough lately. Maybe lifters/ cam related. She has about 125,xxx miles. Original engine. Never been out. I also wanna check and make sure my recent PVC conversion hasn't started to get all gummed up, but she was popping real bad through the carb at her worst.