I have the 1406 carb (600cfm,electric choke) on my Studebaker streetrod. It never idled correctly and drained in 3 or 4 days. I corrected a few problems yesterday and thought I would share what I found and what I did. First, I installed a Mr. Gasket pressure regulator I bought at Advance Auto and set it on 5.5 Lbss. I read where a lot of stock pumps have 10 to 13 lbs. pressure and I also have a electric pump in line to prime my carb after setting ,so this was easier than checking both pumps. Edelbrock wants 5.5 to 6 lbs at seats and I figure I could have been flooding motor. Second ,and most important, I found a built in vacumn leak. Its at front passenger side of carb in the electric choke and takes a 10-32 screw to plug it. After doing these 2 items, my air adjustment screws actually worked at they should and I was able to idle truck at 600 rpms and still put it in gear without killing motor, I think the small vacumn leak was my main problem . I do have another 1406 that has a plug in the same hole, but a new carb at advance auto still had the leak and needed the screw if bought. If you have one of these carbs , please check for the leak.