hello i have a 44 intek with a cheetah cam,dual valve springs, arc rods and flywheel ,heads cut 60 and ported and polished. it has a nikki two barrel carb with the low sides drilled to .030 with adjustable main jet. it runs really good above idle but it runs real rich at idle. at idle for only 10 seconds it is blowing black smoke and engine starts to shut off. i can clear it out and it runs good i was wondering if my timing could be off . i used the search but didnt help much. i can lean the high side down and it will clear up but then it wont accelerate it bogs when i give it fuel any ideas .thank you