What year power steering gear boxes will fit a 66 Chevelle?

Thanks!
Mike

All 64-72 Chevelles and other GM A-body cars. I also think the F-body will work but it has different stops. So the turning radius may differ. I think it is the end cap that is the stop.

You can also swap in Monte Carlo SS, Buick GN, and Olds 442, boxes in from 78-88. They have a different input shaft spline and better 2-1/2 to 3 turns lock to lock. I useds a coupler from a -80ish Chevy truck and it bolt to the steering shaft of the Velle.