piston pounder

As most of you know Im having some BIG problems geting my motor running right. I need to know what float and drop settings work best on a 50DCO. I have the "how to tune" Weber book, and the floats are pictured as being round brass floats. My floats are plastic and are not round but square looking, so I need to know how to set these floats!. Im about to just say F it and take this car to someone if I dont get this fiqured out soon!. Its pretty sad that Im a mechanic and I cant fiqure this out!.

DONNA

in the inverted position (upside down)the tab adjustment is 16mm-5/8",,in the upright free hanging position 51mm-2"