I am running 2X4 holleys 4160 on a stock intake with a 501 lift CP cam in my 427. The motor runs rich (burn your eyes rich) the adjustment all the way out or all the way in no difference. The engine builder said replace the power pumps but Summit would not sell them to me because: First if they are bad it would lean the motor out and Second newer carb are built to prevent damage to the power pump from back fire.
I don't have access to a dyno with an oxygen sensor to test on.
Who is right? What should I do?
