Carb spacer query

[TimDart]

I've just fitted a 1" carb spacer to my Holley 600v/s. Gone for a short run and pulled a couple of plugs to check for colour. the first one (cylinder 4) was light, light brown almost grey whilst the (cylinder 2) plug was more normal with dark brownish electrode. Haven't looked any further.

Should I be adjusting the air mixture or jetting having fitted the spacer?

 

[BJR Racing]

#'s 3 and 4 cylinders are always the leanest on mopars I think that it is to do with how the intakes fuel distribution is along with the cams firing order, chevys have similar problems as there firing order is the same. I took a team G intake and moved the carb 1/2" forward by machining and rewelding a spacer to it and seemed to help this problem greatly. And didn't have anymore leaness on #3 and 4 cylinders.