If you want to use your existing steering linkage, a box from a '62-72 interchanges. The mounting hole (and bolts) are larger in the '67-72 but they'll work ok. I think the factory only put quick ratio (16:1) ones in the '65-9 models but gears were available to convert them so look in all parts cars to see what they have. They also made a replacement 20:1 worm gear for them too. The 24:1 boxes are almost 6 turns lock to lock....the 16:1 is around 4. That's the easiest way to tell.