1968 Hi Boy Axle Swap Questions

[Watasha]

I posted this in the Steering section but wanted to list it here as well. I did some checking and this is my conclusion.

I went to the junk yard tonight and looked at the 2 Ford 3/4 tons. The third was a Dodge and the differential is on the wrong side. Of the two Fords one is a 77 and the other is a 79, both axles were high pinion but did have the correct spring spacing. I can see there is a major difference in the power steering set-ups between these two trucks. The 77 is what I assume to be the "power assist" with a hydraulic ram that pushes on the drag link and the 79 has the hoses directly to the steering box. Both styles have a "push-pull" steering box with a short shaft that runs parallel to the frame and attaches to an arm on the back side of the drivers side knuckle. The drag link runs from knuckle to knuckle along the front side of the axle tube. The 77 steering box mounts inside the frame rail and there is a shaft that comes through a hole in the frame. This shaft connects to one end of the "push-pull" arm and has a device with hoses coming from the pump and hoses going to the ram. The 79 steering box mounted to the outside of the frame rail and the arm connected to the short shaft. After looking at my 68 it appears the steering box is very similar to the 77 with the power assist set-up. So here is what I believe to be true after looking at these two trucks tonight.

1976: Low pinion with "power assist"
1977: High pinion with "power assist"
1978-1979: High pinion with power steering box

I think the "easiest" way for me would be to find a 76 being I am using headers and the high pinion may have clearance issues. I have Stans Headers on my truck and they do come down somewhat close to the engine, but if they did clear it would not be by much. If I have posted any incorrect info please let me know. Also please let me know what it costs to rebuild the "power assist" components as the donor truck has been sitting in the bone yard for some time.