Weber IDF always rich- Please help! Options

[tornik550]

I have dual weber 40 idf's. I cannot get the mixture correct no matter of the changes that I have made. I foul the plugs with dry black soot in only minutes. The car runs fairly well. Could be fine tuned however right now I am working on gross tuning. Heres the background info-

Setup-
-1.7l case now 2.27l by changing jugs to 96mm and crank to 78.5mm
-2.0l heads (I also have stock 1.7l heads, I have had the same issue with both heads)
-A "fairly aggressive webcam camshaft setup for carbs". I do not know the exact lift and such. The previous owner increased the displacement from 1.7l to 2.0l. He changed the cam when he rebuilt the engine. When I rebuilt the engine, I used the same cam. I had this rich mixture issue before and after my rebuild.

Carb info-
-Dual weber 40 idf's freshly rebuilt with new needles and seats
-main jets 120
-air correction jets 200
-tubes- f11
-idle jets 50
-vents 32mm
-floats set at 10mm (rich mixture), 11mm (rich mixture), 12mm (rich mixture)
-fuel pressure at 3.5

Other Info about my engine-
-MSD 6al ignition
-MSD Blaster 2 Coil
-Bosch 050 distributor with pertronix
-Autolite 63 spark plugs gapped at .030

I have tried a few things however I have not been able to change the problem. I only have a set of larger mains which obviously didn't help the issue. I have checked to make sure the needle is seating properly. I have removed the air correction jets to see what would happen- no major change in the mixture. I have a set of 34mm vents on the way however I doubt that will change much. It seems to me that with the carb setup that I currently have, I shouldn't be fouling the plugs after running the engine for only a minute.

Any ideas would be greatly appreciated.

(Yes, I did post something similar on 914Club. I am trying to look for as many ideas as I can find).

[tornik550]

Here is a brief summary of what I have tried to figure out the problem. Some may sound stupid but I have tried everything I can think of. I am referring to rich idle only. Nothing has changed anything. I realize there may be some tricks to get rid of the symptoms however I want to figure out and fix the source my problem. I am absolutely lost and frustrated.

-tried different idle jets (larger was all I had but it was just a shot)
-different main jets of many different sizes
-idle mixture screw adjustments to all extremes
-tried 7 different types of spark plugs at different heat ranges
-checked to make sure pump is not leaking
-tried different float heights- anywhere from 10mm-12.5mm
-confirmed float needle is seating properly
-confirmed air ducts about idle jets are patent
-tried to run without air correction jets just to see what would happen- no help
-rebuilt choke system after I found the starter jets were stuck- no help. out of frustration, i then tried to plug the starter circuit so there would be absolutely no leakage- no luck
-tried various timing setting- no change in rich issue.
-found crack in one intake manifold- no change
-tried different spark plug gaps (0.28-.45)
-tried different venturi size (why not give it a try)- tried 32mm and 34mm
-added the needed o-rings to the idle holders that I forgot- no help

Clearly there is something very wrong. If something were this wrong it seems like it would be somewhat obvious. I think that I have tried just about everything and I am extremely lost and frustrated. I hate the thought of taking my car to the shop but I may have to. I have a young child and my wife is pregnant. I can see her getting a bit angry with me if drop $500-1k taking the car in.