I did a compression test last night. The tester I used didn't zero at zero...it only reset at 21psi...I hope that still means 150 is actually 150.
I tested every cylinder twice with the exception of #3 which I tested 3 times due to the large variance. I followed the same proceedure every time yet got inconsistant results on tests on the same cylinder.The plug in #4 was pretty nasty looking...what would cause this? Anways I was just seeing what you guys thought of these results. I am going to do another test with a different tester this weekend.

#...psi............plug condition
1 135/144 Brown…fairly even, one dark spot to side of electrode
2 150/151 Brown…fairly even, one dark spot to side of electrode
3 148/166/149 Lighter Brown, with a dark spot
4 129/137 Brown/Black…with oily deposits and burned right through around the electrode
5 Compression tester wouldn't fit behind header
6 142/139 Brown…fairly even, one dark spot to side of electrode
7 150/150 Brown…with oily deposits and starting to burn through around the electrode
8 144/149 Brown…fairly even, one dark spot to side of electrode

 

LOL everything ALWAYS happens to cly 5 its the biggest pain in the ***... but still better then the plugs on the LT1

as for the compression test sounds liek cly 4 have a bad ring on it. sounds likes its getting some blow-by

 

the numbers don't mean very much, it's the deviation between them that means a lot and none of your's are really lower than the rest. idealy you'd want all numbers within 10%.

 

you can have all the best stuff in your motor....but the ideal compression should be around 160.

and you might consider purchasing a new tester.