Idle problem

[Andrew]

Just swapped 6 pack intake and carbs for 4 bbl. Now the engine runs rough at idle. seems to surge methodically, not quite a miss, but surges up and down about every second or 2. Also doesn't respond as well to hard throttle. Bogs as if maybe too rich. I haven't gone crazy tuning the carbs yet, just the air fuel mixture to get the highest vacuum, but I think it may need smaller jets? Any ideas?

 

[WileE]

Just swapped 6 pack intake and carbs for 4 bbl. Now the engine runs rough at idle. seems to surge methodically, not quite a miss, but surges up and down about every second or 2. Also doesn't respond as well to hard throttle. Bogs as if maybe too rich. I haven't gone crazy tuning the carbs yet, just the air fuel mixture to get the highest vacuum, but I think it may need smaller jets? Any ideas?

First thing I think of is vacuum leak.