Wanted to give an update. I my above post I described how the #2 plug was turning black and was stumped as to why. I decided to pull the engine back out because I was never satisfied with the way it idled and wanted to degree and or replace the cam. I did a leak down test and all cylinders are 10~13% on the gauge with the exception on #5, It has a 35% leak past the intake valve, you can hear and feel the air escaping from the intake. #7 is the next to fire followed by #2. Since the #5 is still on it's intake stroke while #7 begins to open I'm thinking that when #5 starts the compression stroke, #2 is starting its intake stroke and receiving what is getting pushed past the #5 valve. # 5 & 2 do both share the same side of the intake, dual plane. I think this is why #2 is rich and turns the plug black. #2 also runs about 100 degrees colder than the other cylinders using a infrared heat gun.
What do you all think about this? That's the only thing I can come up with as to why it turns black. I second guessed myself and thought maybe I installed a ring upside down on that cylinder but the leak down and compression results are good.
I was quite surprised to find a leaky valve, When I got the heads we tested all the valves with a home-made tool to seal the ports and pull a vacuum on each valve to check for leaks. More than half of the valves were leaking. These were new heads, I called Brodix and they said to send them in for repair but I decided to lap all of the valves myself. Afterwards all valves held 20"'s vacuum for 15 mins or more and I called it good.
I also bought the tools to degree the cam and after checking I found it is 2 degrees retarded. I have it installed straight up. I have the specs above, open to cam suggestions, I don't think I made a good choice on the cam.
I did take the car to the track, Ran consistent low 12.30's @ 110, 1.7 60'. OK but was expecting more for a near 500 inch motor. 4100# chevelle, Through a full exhaust, 3.73, 2500 convertor. Q-jet ran flawless.
