This is the steering column mounted Reverse and Neutral switch for the 68-72 series Chevelles /  El Camino / GM column auto needs up to some 83 models .. but mainly the 68-72 era.

LOOK AT THE SWITCH 1st.. 7 spades...not 5 or 6 etc.. but SEVEN..

Its for Automatics.. and its on the back of the steering column next to the brake pedal.

Suits  68-72 Chevelle / Cutlass / LeMans / Buick Skylarks.... with  Column Auto & others..  and US full Size cars with Steering column Auto.

and 

NOTE it has 7 splades.