This is the accellerator bracket interior mounted kickdown or whats sometimes referred to as the DownShift  switch ... thats widely used on 69-77 GM vehicles listed below and more.  Look up under your dash at the area you accellerator pedal exits the firewall to see if its still there and looks like the same thing.  If your searching globally for one the GM part # was 1242101.

Fits but not limited to:

1969-77 Chevrolet Chevelle / Monte Carlo; Buick GS / Skylark; Oldsmobile Cutlass / 442 and Pontiac GTO / LeMans, Corvette M-40 A/T