I made a new float for my Model S2 Holly , I have several guestions........how high should the fuel level be in the bowl? Should the new float made of modern composite be the same thickness as the old cork?
Virtually every carburetor will work correctly as far as fuel height goes if the float is set parallel to the body casting edge when the needle is closed assuming you are using the original float hinge.
Needle pressure is basically determined by the amount/weight of fuel displaced by the float less the weight of the float. So yes, the float needs to be the same size even tho the old float probably weighed more than the new material does.