fuel problems

hello out there, I have a 1969 Dart 4dr base/ 225-slant six (Blueblock) with holley 1bbl.....so had car for 4 months had been sitting inside since 05' ran wonderful still did tune up,plugs,wires,d-cap, points,fuel filter..seem to run a little rich...carb also has a perfectly borred 1/8 hole in a angle at the base that lets raw air in? I didn t care carbs condition...on craigs list I got a never mounted Holley 1bbl #1920 remanufactured from the 80's still with holley tag from MI. ....instantly ran great cured miner tunning problems old one was having....still running rich though!....drove fine for last month....all the sudden it wants to dump a lot of fuel and is flooding plugs ...so I lowered bowl level about a 1/4 in (like the old one looked) new fuel pump new hoses ,float needle not sticking & still flooding...cleaned up old carb real good inside and out figuring well it used to get me down the road and Is still flooding!