running rich need help

i have a 87 notch with a mild 302 that has the following mods: trick flow heads( cnc ported) rpm air gap intake( also cnc ported) 650 cfm q series quick fuel technologies carb,1 7/8 long tube mac headers,2.5" off road h pipe,crane cam with roughly .512" lift corrected for the 1.7 roller rockers,k&n air filter with extreme flow top,the block is .30 over,it also has a  pro comp digital ignition,pro comp billet distributor with no vacuum advance,and pro comp coil.I am running ford racing 9mm plug wires and auto lite 3922 plugs gaped at 50 thousandths and 110 gph fuel pump. the problem is the car seems a bit rich at idle just a faint rich smell coming out of the tail pipes. What should the carb be jetted at? Right now it has 71 in the primary side should i drop that to a 67-68? or would the 110 gph fuel pump be putting to much fuelpressure on the carb and making it a bit rich.The car did have a 750 carb on it that was jetted 69 on the primary side with a stock  fuel pump and it never ran rich so now i'm  trying to decide where to start any help would be very appreciated  

wow no one??  

nope....

but... main jets will not effect idle mixtures...    idle mixture screws will.....  blown power valve..  too much fuel pressure overpowering the needle and seats.   causing the fuel level to pour out of the booster venturi...   the normal way is the airflow lowers the pressure through the venturi and pulls the fuel up and over...  this does not happen at idle as there is not enough air flow across the venturi....  


idle feed restrictions will affect off idle transition port feed and get rid of the hard to cure after everything else is fixed  flat spots off idle..


there are tons of books on holley carbs...    much to learn...


pop you carb off... flip it over... take a look at the front of the primary throttle plate bore... where is the throttle blade...

only the round hole should be exposed...   the slot should not be...  the slot is the idle transition port..  if you throttle blade is too far open.. fuel can be pulled from that slot.. that might be your too rich problem...

is you carb equipped with 4 idle mixture screws..  ( i did not look at your carb number if you posted it... ) holley has made thousands of carbs... each a little different..    

i just swapped a 4180 onto my ford van... it is a factory ford carb build by holley... it has 4 idle mixtures screws in the base plate..  so you can fine tune the idle mixture... and a secondary idle speed screw...  

normal holleys have idle mixtures screws in the metering blocks...    where are yours set at...????  i find most of the holleys i have seen .. usually between 5/8th and 3/4 turn is where they work best at..  i am talking about the ones on the metering block...


how much manifold vacuum do you have at idle... with the trans in park...    how much with it at idle and the trans in drive..  if it is an automatic..  

the carb is a brand new quick fuel technologies 650 race carb, it does have 4  air screws located in the metering blocks, the power valve is not blown as the carb is only 2 days old and it has never back fired.As for vacuum i'll check it this week end at idle,the car is a 5 speed.it also has a secondary air flow adjustment.it was a custom built carb from quick fuel to match as close as they could to the combo in my car.Hopefully with so,e wrench time this weekend i can get her sorted out thanks for the valuble input this is the carb i have http://www.summitracing.com/parts/QFT-Q-650/  

start with a screw driver... see where all 4 idle mixture screws are at...    how far open... or

read the thick tuning manual that should have come with the carb..