Hi Bill,remember HC is unburned fuel - raw gas, CO is partialy burned fuel - rich mixture. I agree with strickly P, back the timing off to pass the test then adjust it to perform. Use the mixture screws on the carb to get the highest idle, then lean it to get a 50 rpm drop (the lean drop method). But you may not be able to over come a radical cam. To help set the idle 50 rpm under the max alowed. In Colorado its 1200 rpm. For the CO under load install a smaler set of jets. You may have to purchace an adjustable metering plate for your holley. I think the factory metering plate is equall to a 70 or 72 jet size. Try dropping it to a 66 jet. Hope this helps
