Are the power steering boxes the same for a mid 60's to late 70's chevelle, monte, elky, nova, or camaro? I am looking for one and I am not sure if it matters what car it is from.

A '72 Lemans variable ratio power steering box was a direct bolt in to replace the standard box on our '69 Chevelle.

There were many different gear ratios, travel, and valve efforts. This paper takes you through the installation of a 12.7:1 fast ratio power gear into early A-cars or F-cars.

http://www.corvettefaq.com/acar/A&F-CarFastRatioGearRev24JN05.doc

At this www.corvettefaq.com/A-car.asp websight there are several spread sheets that have lists of power steering gears that can interchange into older vehicles.

Hope this helps,
Jim