[cosbytnkid]

Holley's are a good carb. I had a 780 CFM on a 390 powered '67 mustang. From what I'm reading here I would definately check mechanical advance under the plate the points ride on and make sure the weights aren't hanging up. I used to take a shot of carb cleaner in a spray can to clean 'em up. Every so often I would take the sight plug off on side of the fuel bowl. First I would check to see if fuel level was at bottom of the hole making sure my fuel level was OK. Then using same carb cleaner with spray nozzle shoot a goodly supply into fuel bowl and hurry to replace sight plug before I lost everything leaking down side of fuel bowl. I would then set the engine on high idle manually about 1900 RPM or so and just let the car run for about 5-10 minutes this way. What I was doing was letting carb cleaner mix with gas and running it through the carb to help keep it cleaned out. Also do you have a filter between fuel pump and carbureator? If not get one installed. Good insurance against a slug of dirt getting into your carb. I don't know about the newer Holleys but the older ones had your mixture screw on each side. What I did was using 1/2 turn increments turn the adjusting screw in leaning out the mix until the motor started pulling down. Noting the position of screw, like at 12:00, 3:00 oclock position I would using 1/2 turns start backing the screw out until the engine pulled down again. Taking toltal of 1/2 turns I would divide by 2 and set my mixture screw in that position so I was exactly half way between it's leanest setting and carbs richest setting and the engine usually ran pretty well idling. But that was from a long time ago. I don't know if things have changed in the last 30 years or not. Also I'd get my hot idle screw set to where the engine seemed to idle at the smoothest. I hope this might help you out.