Holley 1920 Very slight stumble...

starting in 1968 all / most chrysler engines had a lean i idle circuit. the carter carbs can be fixed by drill ing the idle tube. and are easy to drill. most are .032-.035". takes a spacial drill bit and steady hands. and you only drill .001"-.002" at a time. but the holley carb is near impossible to drill. the tube is inside the metering block. i did one once but it took all afternoon to fix the metering block.