Carburetor linkage

[mightymouse713]

My father-in-law has a 1959 Thunderbird with a 352 automatic. He has a holley carburetor on top of his rebuilt engine. The linkage is such that when you depress the accelerator pedal there is a pivot point that doesnt move the carb's throttle until about 2 inches of pedal push. Is this the original type of linkage and why is there a "dead spot" of pedal before actual acceleration?
Thanks!