Steering box options
 

I need a steering box for my 68 Malibu. What models/years will work?

Have you considered swapping in a steering box from a Jeep Grand Cheorkee?

You can put in a 93-98 GC box either rebuilt from a part store or from a salvage yard. You then need a new rag joint and some cheap fittings (which can be found here, http://lee-powersteering.com/rebuild-misc.htm )

Can be pretty cheap if you do the salvage yard route or maybe $150 if you buy from part stores. All-in-all, it provides a much more firm steering feel which helps when you are at highway speeds.

Pretty sure the gearbox is the same for 64-72 Chevelle, probably any GM A body. and a lot of other cars. Just have to make sure the hose fittings are the same. As mentioned the JC gearbox is pretty much the same, different size fittings, and rag joint. Agree with Eric, now would be a good time to change to a tighter ratio gearbox. AGR makes a 12:1 replacement box, direct fit but they're pricey. I believe there are some remanufactured units with a 12:1 ratio or the Jeep gearbox.

I've done this JGC conversion on about a dozen Chevelles...including the '66 Sedan presently in my shop.
Awesome swap!!
The box MUST be from a '93-98 Jeep GRAND CHEROKEE only!! And the rag joint needed is P/N Lares 200 found @ Advance Auto.

Forgot to mention, some gearbox's allow fewer turns lock to lock such as the Camaro gearbox from that era. Outside is the same, same gear ratio and is a direct bolt in, except for the internal stops allow fewer number of turns lock to lock. If you use one of those it will limit how far you can turn the wheel on a Chevelle, no more sharp turns while trying to park, etc. So be careful.