There are two manual steering boxes on '69 and '70 models, a 16:1 and a 19:1 plus the power box which is also a 16:1 ratio but different tag #. So in essence both people are right, kinda...

I am not sure if you can use the manual tight ratio box with the rest of the power steering components. I'll hhave to check my parts catalogs for reference when I get home from work tonight.(sold auto parts when I was younger and got a complete catalog rack when I left as they were just starting to put comtuers in back then)

 

Wow, thanks for all the useful information. I'm still waiting to hear back from the seller about which parts are included in the kit.

After investigating all the options, I'm now also torn between getting stock Power Steering and one of those bolt-on aftermarket rack-and-pinion kits. I plan on using the car as a regular driver 7 months out of the year, and quality steering is really crucial in these types of driving conditions. When driving the car in its current manual steering state, I've found a lot of play in the steering at high speeds, along with moderate drifting on the highway. To those of you who've upgraded their steering, would you recommend stock PS, or R&P? Is there a downside to R&P, apart from the extra 600$ price tag?

 

I'd be curious to hear about the R&P conversions. I have a Cavalier power rack sitting here that I was thinking of transplanting into my car ala Sixto Bernal, but a complete and ready engineered package sure is tempting.

I was planning on the R&P upgrade to do away with the loose feeling of the stock steering, mine is a 69 with the 16:1 manual box. If you have the money to spend on the R&P, I would certainly entertain that option.

If you want me to check the part numbers for power steering to non-power steering for you drop me a PM and I'll dig out the big book of Moog.

 

The power steering box and hydraulic linkage from the 1970 Mach will fit on your 1970 Fastback. The only difference would be if you are talking about different engines, then there will be some pump brackets changes needed.

The 1970 centerlink is different from all other years. The holes for the inner tie rod ends are larger, but the hole for the power cylinder mounting is not. The power cylinders are the same from 1967 to 1970. You can install a 1968-1969 hydraulic linkage assembly on the 1970 if you use 1967-1969 inner tie rod ends.

Your manual steering car, unless the box has been changed out or the car came with a certain handling package, will have the slower ratio box. All power steering cars have the quicker ratio box. You can use the quicker box in a manual car, but it will be harder to turn. You can also use the slow ratio box with the power steering linkage and have a very easy turning car.

Steering box rebuilders install new bearings and seals, but not new major internal parts since they are not available. There were some repro internal parts available at one time, but they were made in Argentina and are poorly made. A good rebuilder replaces original worn parts with good used parts. You can also buy a new repro steering box, but it is also Argentine made, has some quality problems, and has a warranty no better than a rebuilt box.

Figure that any used system you buy is going to need a complete rebuild.

For steering response, road feel and tightness, nothing will beat a rack & pinion setup. A properly rebuilt factory steering box and power steering system can be a good performer, but it will always be at least a little inferior to R&P. However, R&P systems have a greater turning radius when installed on early Mustangs, some units worse than others. If you drive and park the car a lot, this can cause problems in parking and turning your car in tight areas. The better R&P conversions are also the more expensive. The cheaper units will require more owner engineering and modification to make them fit and work. If you are not very mechanical, you would be better off buying a top line setup.