spark plug dilemma

[wireweld]

On my 416, I pulled the plugs today because I had a miss off idle. I saw that the front plugs were running rich and the back plugs were lean.
cylinder #
drivers side
1 dark brown
3 brown
5 whitish brown
7 white with specks of brown
passenger side
2 black
4 brownish black
6 brown
8 white
It appears that the front is rich and getting leaner as we go back.
Should I mess with the idle screws or is this something else?
The primaries are screwed out 1 turn and the secondaries are 3/4 turns out.

 

[1wild&crazyguy]

square the idle settings, all 4 corners the same.

try 3/4 - 7/8 on all 4.

 

[drjay0]

I agree with the above but want to add to check your rear float level. Also a possible vacuum leak at the rear of the intake. Those rear cork gaskets are tricky and usually need a generious dab of sealer at the corners.