Anyone know what this is or where it goes? Came off a '62, was found in a parts box when the car was purchased.

Thanks!

 

Steering box bracket and steering stop

 

That's the mounting bracket that goes on both sides of the frame to support the steering box!

 

The piece that is longer goes on the inside of the frame, closest to the motor.

 

The above are correct.
The part with the three holes goes on the OUTSIDE of the frame, between the frame and the steering box.
That is a spacer which was ADDED to the V8 cars (not used on 6cyl cars) to move the steering box/column outboard to provide added clearance for the left side of the V8 engine/exhaust manifold.
There is a particularly noticeable effect (which I bet MOST of you have never noticed) that is caused by moving the steering box outboard. It is MOST noticeable on 56-57 Vettes.
When sitting behind the steering wheel, and looking straight at the relationship between the horn button and the speedometer (more so on 56-7 cars), they are NOT LINED UP with each other, because the steering wheel is slightly to the right of the center of the speedometer.
Also, in the engine compartment, on the firewall, 56-later cars have a metal plate around the steering column------------WHICH IS NOT PRESENT ON 6CYL CARS!!!! On 6cyl cars, the upper/lower firewall seam on each side of the steering column curves around the column. On 56-later cars, a portion of this seam is cut away on each side of the column and the hole through the firewall is enlarged to the left for compensating for the steering column being moved over to the left.
Never noticed this? Check it out the next time you get to compare this area between a 6cyl and a V8 car.

 

Awesome guys, thanks!