Late Model Steering Box Q

[AusTruck]

I got a complete hydroboost setup I'm looking to install on my 69 C10. One of the few factory options my 69 came with was power steering. The original box does appear to work well as does the PS pump.

I've seen adapters to run a late model o-ring box with the early IFF hoses, but not the other way around. I.E. to run late model o-ring hoses with an early IFF box. One option I've researched from here when doing the hydroboost conversion is guys have a custom PS hose made with one end o-ring from the hydroboost and the other end IFF for the early box.

I was thinking about just going to a late model box that has the o-ring fitting, using the o-ring hose from the hydroboost and being done with it. So as far as bolting in a late model box

1. Will the late model o-ring boxes bolt to the frame without mods? My checking here seems to show it will.

2. Will the late model box bolt directly to the steering shaft, or will I need some kind of adapter/coupler? Another way of saying this is are the splines on the steering shaft connection the same, late box to early box?

3. Finally, which pitman arm should I be using, from the early IFF box or from the late o-ring box?

Thanks to all, this site has been a great source of info.