my dad has got a chevy zz3 350 in his 54 stude truck. its got a 600 edelbrock carb. its been trouble free for about 10 years. now , at idle it seems to be running on 4 cylinders. when you ease down on the throttle a little it kind of skips and stumbles and then all of a sudden it runs great. i have taken the top off and examined the floats and needle and seats. there is a good amount of trash in the float bowls and in those little screens.i'm gong to clean and blow out the whole thing but i would really like to know whats wrong and pinpointing the problem instead of cleaning it and hoping that its fixed.it seems to me that its in the idle circuit.thanks in advance.