Edelbrock part throttle surge help

ok i am thinking of the AFB on stock chrysler big block. sorry. but the 5/16 does work. i had a 1965 300 L 413 stock AFB. the plugs was a little lean. so i bumped the float level to 5/16. then the plugs looked very good. i tried the 5/16 cause i had a bunch of spec sheets for the AFB on many diff engines. and they showed several diff levels. so i thought i could try a small change. and on the old AFBs they had some floats with a ribbed side and some with smooth side. each having a diff level. but cant remember what the diff was.